Part II

The Augustan Process

The First Julio-Claudians


Julius Caesar (Dictator 48–44 BC).


Augustus (30 BC–AD 14). (Adobe Stock)


Tiberius (14–37). (Adobe Stock)

The Later Julio-Claudians


Gaius (Caligula, 37–41).


Claudius (41–54).


Nero (54–68).

Chapter Two

The First Imperial Family

Augustus established the pattern and the process for the selection of an imperial successor all too clearly: he was to be selected by the ruling princeps, and this was his responsibility and his alone, though no doubt intrigue and influence went on that was designed to inform or distort his choice. That choice, as was shown in Augustus’ long search, which he had had to repeat several times over during his reign of more than forty years, was restricted to members of his own extended family. The signal that he had made his choice was the adoption of the chosen successor as his son. If the successor so chosen was still too young, a guardian-princeps, an Agrippa-figure might also be chosen.

It was intended that the successor would have gained extensive experience of political administration and military command during the reign of his adoptive father, a process of political education that could scarcely last less than a decade, given the complications and personal nature of the Roman system and the size of the Empire, though the deaths of three of Augustus’ chosen men on their travels was a sign that it might be better to keep them in Rome. This process of education and induction could only be completed after the reigning emperor died, when the Senate must signify its acceptance of the new emperor by a sequence of actions, including the award of the necessary tribunician and proconsular powers if they had not already been awarded, the offering of oaths of allegiance by the current magistrates, the administrative officers, the senators, any army commanders and officers who were present, and any members of the public who were present and wished to do so.

There were therefore three sets of people who had to be involved in the selection and installation of a new Roman emperor: the imperial family, in particular the reigning emperor; the Senate, whose task and formal power it was to invest the chosen man with the imperial powers, a role which at least theoretically carried with it the power to refuse to do so; and the people, whose role was largely passive but who had to be involved, even if only as spectators, in order that the succession was seen to be public and publicly acceptable. In addition, the presence of the Guard and the army mutinies on the death of Augustus were signs that the soldiers, whose units were organizationally descended from Julius Caesar’s own troops, would need to be involved as well in some way.

The ceremonial installation of Tiberius in the Senate was not strictly necessary, since he already had all the powers needed for assuming sole power, but it was required to convince the public that the thing had been done properly. Tiberius himself had hesitated, or delayed, in assuming full control, supposedly in the hope that the Senate might be induced to take a share in the burden; more probably it was to compel the Senate to insist publicly that he take on more of the powers. Like his insistence on Augustus’ public announcement of Tiberius’ own status as heir, this forced the Senate into a public declaration it could not revoke.1

There was thus a disjunction in the various elements involved in a succession, or at least there should be. The choice of the man and the award of the powers should properly precede the installation ceremony, and should have been publicized. This would ensure a smooth takeover of authority and eliminate possible confusion. Above all, the chosen successor needed to be publicly identified before his predecessor died; if he was not and the choice remained open, there was no obvious procedure for finding a new emperor other than a discussion in the Senate, and probably a vote there.

At a distance from Rome the oath-taking was repeated in all the army camps, and in all the cities and the administrative centres of the Empire. Here was clearly a danger point if the successor was not clearly signalled in advance; the procedure of oath-taking might be pre-empted by an ambitious interloper. Augustus had also, posthumously, added one more element to the process: potential alternative successors could be killed out of hand. It was clearly going to be more convenient to eliminate challengers and potential challengers before the emperor’s death; the potential for killing was considerable. The potential for disruption by the untimely death of an emperor was even greater; this was the inevitable penalty of monarchic rule.

The will of the deceased emperor would be found and read, if there was one. Augustus had been very careful to specify that all the soldiers, the citizens, and the senators should be rewarded. Of these groups, the riots by the German and the Pannonian legions had shown that it was the army that had to be attended to most carefully. Tiberius, an experienced commander, had first ensured that the Praetorian Guard at Rome was his, and only then had he attended to the Senate and the citizens. The Guard was clearly vital since it was the only body of professional troops in Italy. The armies on the frontiers had been eventually quieted by attention paid to the grievances of the soldiers and by the gift of money from Augustus’ personal fortune, in accordance with his will.

Mortality ensured that, as soon as an emperor began to reign, the question of his successor became insistent. Augustus’ long quest was partly responsible, but the main reason was that life was short and emperors were very vulnerable. Tiberius was already over the age of 50 at his accession; that he would live to reign for another twenty-three years was unexpected. These men lived in public, they met all sorts of people and they had many enemies. Tiberius survived a plot as early as in his first year.2

For Tiberius there were two ready-made heirs, his own son Drusus and his nephew and adopted son Germanicus, both of whom were adult and had shown their loyalty to him in facing down the mutinous soldiers, and both were capably employed in conquering Germans. Furthermore, both men by now had sons of their own. Drusus was married to the former wife of Gaius Caesar, Livilla, the daughter of Tiberius’ brother, and they had a daughter, Livia Julia, and twin sons; all three of them were still children. Germanicus was married to Agrippina, the daughter of Agrippa and Julia, and so a granddaughter of Augustus, a fact that she never let anyone forget; she was therefore a sister of Gaius and Lucius Caesar, and of Agrippa Postumus, all now dead. (Had she been male, she would in all probability have been emperor, or already murdered.) She and Germanicus had six children: three boys – Nero Caesar, Lucius Caesar and Gaius, this last called Caligula by the soldiers from his being exhibited to them in small versions of the soldiers’ boots – and three daughters: Agrippina, Drusilla and Julia Livilla. The two eldest children of the two families, Nero Caesar and Livia Julia, were soon married to each other. (Note that the intermarriages within the family were continuing.)

There was thus a considerable bank of blood relatives on which Tiberius could draw in organizing the succession, spread over three generations (and there was also the disregarded Claudius, Germanicus’ younger brother.) However, as Tiberius lived on into his 60s and then into his 70s, he faced the same problem that had plagued Augustus. The initial long list of possible heirs that existed in AD 14 was gradually reduced in size over his reign until there remained only two.

The process of reducing that list was, as with Augustus’ list, a chapter of accidents, illnesses and intrigues. Germanicus died on an Eastern tour in AD 19, leaving his vengeful widow Agrippina and their six children, who thus now became much more likely possibilities for the succession, not least in the view of Agrippina. Until his death, Germanicus had been the most likely choice. He had been consul for the second time, along with Tiberius, in AD 18, whereas Drusus had only one consulship to his name. Also Germanicus was on a major political and diplomatic journey through the East (just as Tiberius and Gaius Caesar had been in the past) when he died. Rumours of murder, of course, circulated.

Tiberius had been using Drusus as his commander in Germany (a task Germanicus had already undertaken with some success) and he triumphed in AD 20 after the conclusion of the war in Illyricum. Next year, if not before, he was clearly marked out as Tiberius’ new heir. He was consul in 21, along with his father Drusus, for the second time, Tiberius for the fourth, and was now nominated as the chosen successor. Tacitus’ summary of Tiberius’ letter of recommendation to the Senate is a concise statement of the qualities required for the future emperor: he had had ‘eight years’ probation, including the repression of mutineers, completion of wars, a triumph, and two consulships’, so that he ‘knew the work he was to share’, and in addition he was married with three children and had reached the age at which Tiberius had assumed similar responsibilities.3

So, in the year after his consulship Drusus was invested by the Senate with the tribunician power. The proconsular power is not mentioned and was probably omitted; it could be awarded when needed, or perhaps it was now subsumed in his position as recognized heir. Then, next year, in 23, he died; it was later alleged that he had been murdered on the orders of L. Aelius Sejanus, the emperor’s confidant and Commander of the Guard, by means of a slow-acting poison. However, accusations against Sejanus after his death are hardly firm evidence, and a slow-acting poison’s symptoms may be the same as those of any number of diseases. Drusus had certainly been Sejanus’ enemy and competitor, and had complained that Tiberius heeded the confidant more than the heir; the very fact that Drusus uttered these sentiments aloud suggests that discretion was not his major virtue; he was also said to be all too fond of wine. His death was hardly unusual; it was just another case of a prince who died while still young.

The series of appointments and adoptions arranged originally by Augustus in AD 4 after the death of C. Caesar and the return of Tiberius to favour had clearly been an attempt to organize a succession for the next two or three generations. (See Genealogical Table IV.) Indeed, Tiberius’ position was rather like that intended for Agrippa, as ‘emperor-regent’ until the next generation, specifically Germanicus, was mature enough to take over. It is certainly the sort of long-range scheme that Augustus was capable of devising, though by then it should have been obvious that chance intervened all too readily. If he had so devised it, the plan was now in ruins.


Tiberius now faced the same problem as Augustus had repeatedly encountered. (For Tiberius’ possible selections, see Genealogical Table V.) Germanicus had been adopted, and then Drusus had been specifically nominated, but their deaths had followed soon after their nominations. Even before Drusus’ nomination, Tiberius had been looking, as Augustus had been, to the next generation. In 20 Nero Caesar, Germanicus’ eldest son, was promised a five-year advancement in the age at which he could stand for office, and his younger brother Drusus Caesar was now linked with him in this. After Germanicus’ death Drusus had acted as their protector, so that while he lived, the outline of the succession was reasonably clear to all; on his death, however, the presumptive heirs were still only children, and so were too young to be considered as successors. Germanicus’ eldest son was 14 in AD 23, so an adult protector would clearly be needed if Tiberius died, and he was 65 in that year.

It is possible that Tiberius saw his Guard Commander, Sejanus, in the Agrippa-role of emperor-regent and protector of the heir for a time. Sejanus had spotted a means to power by using the Guard, which he concentrated into a single fortified barracks overlooking Rome, and he gained Tiberius’ trust as few others ever did. Sejanus’ power certainly expanded in the later 20s, and he set his sights on greater things. He was widely disliked in the Senate, of which he was not a member until Tiberius awarded him a consulship, and he had to operate mainly through his imperial contact.

Whether he really contributed to the successive removals of the potential heirs is not always clear, but suspicions existed and grew. Of the possible heirs after Drusus’ death, the sons of Germanicus and Agrippina were now the eldest, but Drusus’ son was also clearly available. The steady elimination of these children until only one was left could easily be blamed on the powerful and unpopular Sejanus, even if it was not true. One of the twin sons of Drusus died in the year after his father, but his twin Tiberius Gemellus was still alive when the old emperor died in 37. The two eldest sons of Germanicus were removed, first Nero Caesar into exile in 29, where he died a year or so later. Nero Caesar had been seen by all as the likely heir, and Tiberius had indicated as much in a letter to the Senate in 25 when he indicated to Sejanus that he might be his choice as regent.4 However, Nero had become involved in a plot against Sejanus and this led to the boy’s exile. He might also have died a natural death, even if he had not been in exile.

Sejanus himself fell from power in dramatic fashion two years later. Tiberius sent his new Guard Commander to the Senate to read out a list of Sejanus’ misdeeds, on the day when Sejanus himself was expected to be given new powers; he and the Senate were taken by surprise, but while the first was dismayed, the senators were jubilant. Then in 33 Drusus Caesar was condemned to death by starvation. In all this only Drusus Caesar was actually killed, perhaps because Tiberius came to the conclusion that he was unacceptable as his heir. He had the curses that the starving man shouted as he died read out to the Senate, presumably believing this would convince the senators that he really was an unsuitable candidate. In fact, they read more like the uncomprehending rage of an innocent man wrongly condemned.

The series of deaths seems to replicate hideously those under Augustus. Sejanus was held responsible for the removal of Nero Caesar and the disgrace of Drusus Caesar, but it was only when he began a similar denigratory campaign against their younger brother, Gaius Caligula, aged 17 in 31, that Tiberius decided to remove him. The emperor was then left with only two possible candidates for the succession: Gaius and his cousin Tiberius Gemellus. Yet at the same time that this ‘dynastic catastrophe’, as it has been called, was taking place5 in the form of the long line of royal family deaths that stretched from AD 19 (Germanicus) to 33 (Drusus Caesar), the emperor was also acting to preserve and increase the number of political heirs. He took Gaius and Ti. Gemellus to live with him on Capri, which removed them from the intrigues, backbiting and plots of Rome, and may thereby have preserved their lives. However, it also prevented them from developing their political, military and administrative skills which they could only develop by living and working in the city and with the army.

Tiberius had clearly modified the requirements in an heir that he had listed when recommending his own son to the Senate ten years before. Now there could be no question of an extensive training in Roman politics or in military affairs; the city was too dangerous. After the deaths of the children of Germanicus he had decided that keeping his heirs alive was now the priority, and that only he could do it. In contrast to Augustus, who had faced the same problem, he now had no Tiberius- or Agrippa-figure to rely on; he had to do the job himself.

The womenfolk of the imperial family were, however, also attended to, their marriages being clearly arranged for dynastic purposes. The elder Agrippina, Germanicus’ widow, died in 30, still angry, just as her two eldest sons were being brought down by Sejanus. All three of her daughters were then still alive, and as they reached the appropriate age, the emperor chose husbands for them. The eldest, another Agrippina (usually called Agrippina II) was married in 29, the year her brother Nero was exiled, to a representative of the high Republican nobility, Cn. Domitius Ahenobarbus. He was also a grandson of Octavia and M. Antonius, so this was a marriage within the extended imperial family and between people of equal rank. The other girls, Drusilla and Julia Livilla, were both married in 33, but this time their husbands were of much less distinguished origin. Drusilla was married to L. Cassius Longinus, consul in 30, a noble family perhaps, but as a descendant of the assassin of 44 BC, hardly a competitor for the supreme power; in addition, he was plebeian, and was the younger of two brothers and the lesser of the two in reputation. Julia Livilla was married to M. Vinicius, of a family only fairly recently consular, the son of one of Augustus’ generals, an orator but of no particular distinction or descent. There was also the sister of Ti. Gemellus, Julia, Tiberius’ own granddaughter, who was the widow of the deceased Nero Drusus. She was now remarried, this time to a man of even less note than Longinus or Vinicius, C. Rubellius Blandus; he was elderly (he had been consul as far back as AD 15) and the grandson of an eques (knight).6

These marriage choices were no doubt quite deliberately made by Tiberius with the intention of removing these women, who had to operate politically through their husbands, from political affairs. It did not wholly work, for the proximity to imperial affairs that their husbands had achieved by these marriages stimulated ambitious thoughts in at least one of them. So the intended reduction in the women’s interest in the succession was entirely denied by the increase in their husbands’ interest; the women may well also have felt insulted by their apparent demotion. For the present, however, the undistinguished husbands largely removed the women from consideration as political players, and any children would not be adult for many years. This policy thus did succeed in concentrating the emperor’s succession intentions on the two cousins, indeed specifically on Gaius.

Tiberius was fully aware that once he was dead and Gaius was emperor, the life of Ti. Gemellus was effectively forfeit. He was destined for the same fate as Agrippa Postumus and for the same reason. The old emperor is recorded as weeping as he clutched the boy to him, and crying to Gaius, ‘You will kill him.’7 This was not a personal instruction, but a statement of the political necessity that Gaius would be under. Tiberius himself had largely escaped blame for the killing of Agrippa Postumus by scattering that blame over Augustus, the centurion who did the deed, and the ‘confidant’, though he did not prevent the starving to death of Drusus Caesar for exactly the same reason as was given for Agrippa’s killing: his unsuitability to be emperor. He could not afford, however, to kill either Gaius – who he clearly favoured as his heir – or Ti. Gemellus, in case one of them died before him. So many princes had died in untimely fashion that it was clearly necessary to have at least one spare one available.

Gaius had therefore emerged as the emperor’s choice for his successor in the same way that Tiberius had for Augustus; he was the only candidate still alive and adult when the old emperor died. The difference was that Tiberius had by that time had long experience of all the intricacies of the Roman political system, whereas Gaius had effectively had none, apart from the experience of living in the closed world of the court of a world-weary paranoid recluse secluded on the island of Capri. To be sure, it took a certain skill to survive this experience; he is thought to have had a hand in the downfall of Sejanus, though since he was no more than 18 at the time this would seem to be excessively precocious of him. Yet the experience of years in Capri was not the sort that would help in manipulating the Senate, the magistrates, the governors or to command the army, for which charm, courage and an outgoing political intelligence were much more useful. Within the group around Tiberius he was clearly the heir, and was recognized as such, and as the old emperor’s strength faded, the allegiance of those present with him shifted towards the obvious successor. Tiberius did not actually designate Gaius specifically, nor did he arrange for him to be awarded the necessary imperial powers, but then he did not need to. Ti. Gemellus was the only alternative and he was still too young, younger even than Gaius. When Tiberius finally died, possibly assisted into death by the Guard Commander Q. Naevius Sertorius Macro (another beneficiary of Sejanus’ fall), Gaius automatically became princeps without question.8

Gaius therefore became emperor at Tiberius’ death-bed, not by the nomination of Tiberius, though his preference was clearly known, but by the collective decision of the courtiers present in the death chamber, led by Macro the Guard Commander. The Senate and the army were presented with a fait accompli, and, while the soldiers, at least the legions in Germany, had fond memories of ‘Caligula’, the Senate was surely less than happy about the situation and any apprehensions the senators had were, of course, fully justified.

So the new princeps took power without having been awarded the institutional offices that were required to operate the political system, without being nominated by the preceding emperor, and without any training for the office. Tiberius had already had those offices – tribunician and proconsular powers, now simply described as the ‘imperial powers’ – when Augustus died, and he had also gone through a long and careful programme of public acceptance, resolutions and votes in the Senate, public oath-taking, and so on. This time matters were organized very differently.

The Guard Commander, Macro, did the organizing, and he had clearly thought out the problems beforehand. Once again, as with Augustus, the emperor had co-operated by reaching a great age and then dying slowly, so that such arrangements could be made. Macro had contacted certain senators and discussed the matter with them well in advance. This included one of the consuls of the year, a distinguished legal expert, Cn. Acerronius Proculus, who worked quickly to pre-empt any possible opposition, particularly in the Senate.9

In the event the Senate as a whole was more than pleased to be rid of Tiberius. He had shown his contempt for senatorial servility too often. Senators co-operated fully in the process designed by Macro and Proculus. On the night following Tiberius’ death, Macro sent letters to the provincial governors reporting the death, and reporting the accession of Gaius, who was provided with the title imperator,10 by which he was saluted by the soldiers at Misenum as soon as the death took place. This was no longer simply a title awarded either by the soldiers of a victorious Roman army or by the Senate in recognition of a victory, but had become an alternative title to princeps, indicating the word it eventually became in later languages: ‘Emperor’. Language was shifting to accommodate the realities.

Note that Macro did all this once Tiberius’ death was certain, and without consulting anyone other than, presumably, Gaius himself. Yet it is particularly significant that his letters to provincial governors and army commanders were accepted by their recipients, and that the news they contained was acted on at once. We know of two widely-separated reactions to the news. In Jerusalem, the governor of Syria immediately took oaths of allegiance to the new ruler as soon as he received Macro’s letter; in Spain, the governor of Lusitania did the same.11 Neither of them, and presumably no other governor or commander, waited for the official word from the Senate.

The Senate, however, also acted quickly. Two days after Tiberius’ death, on 18 March 37, it was convened and immediately annulled Tiberius’ will. This was clearly done by prearrangement – the lawyer Proculus who was consul at the time was obviously involved – and was done because Tiberius had made Gaius and Ti. Gemellus joint heirs to his estate, perhaps in an attempt to preserve Gemellus’ life, though given his youth it was certain that Gaius would be in charge. (The problem had not arisen with Augustus’ will because he had left the largest part of his estate to Tiberius, and the rest to his wife Livia, Tiberius’ mother, whence it was eventually to go to Tiberius; later imperial wills were so regularly annulled that emperors stopped making them.) The annulment of the will, however, also involved the cancellation of his bequests to other individuals; Gaius solved the problem by giving the bequests as personal gifts and adding a bonus on top.

By doing this, the Senate in theory had also annulled Gaius’ position as princeps/imperator. In fact, the Senate had not had any say in the succession. Macro’s letters had bypassed the Senate on the way to the army and the provinces, and the fact that it was the Guard Commander who was orchestrating the succession meant that the section of the Guard that was stationed with the emperor in Campania and at Misenum, the naval base, took the oath of allegiance as soon as Macro could administer it; the Senate was thus not involved.

What is more, any possible objections in the Senate were also pre-empted by the popular reaction. Gaius repeated the slow journey from Campania to Rome that Tiberius had made, walking behind Tiberius’ coffin dressed in mourning, but this time the public reaction was joyful and Gaius was greeted with cheers and acclamations along the whole route. This public acceptance tended to pre-empt any discussion or objections the Senate might have indulged in. So when Gaius reached Rome on 28 March and met the Senate, the whole set of powers and titles that Augustus had spent decades sorting through to achieve the correct and judicious balance of powers was granted to Gaius in a single act.12

This set of events was similar to those that had occurred when Tiberius succeeded Augustus – indeed, the funeral procession was deliberately copied – but the individual elements came in a significantly different order. Tiberius did not need a grant by the Senate, which for Gaius came last. However, Tiberius had made sure that his very first act after Augustus died had been to give the watchword to the Guard, which ensured that he was in command, and this in effect was what had happened when Macro ensured that the Guard at Misenum hailed Gaius as imperator, and told the generals and governors of the succession. Tiberius and Gaius, therefore, both had a keen appreciation of the immediate realities of power: the Guard first, then the Senate. The popular acclamations were a bonus but not essential, though they had proved useful in persuading the Senate, to which a certain deference was shown in the voting, rather than the assumption, of the final legal imperial powers. The order of events therefore had been acceptance by the Guard, then by the people, and then the imperial powers were voted by the Senate.

Gaius was accepted, but it was because of his proximity to the dying emperor that he had been nominated, and his elevation had turned on Macro’s control of the Guard more than his acceptance by the Senate. This sequence, much clearer in Gaius’ accession than in Tiberius’, makes it certain that it was still control of the army that was the vital element. Macro had, in fact, carried through a skilful coup d’état. It was possible to do so because neither Augustus nor Tiberius had legislated for a clear succession procedure. This was Augustus’ fault. He had refrained from establishing an imperial regime by law, preferring a ‘restoration of the Republic’, and this meant that the position of emperor remained legally anomalous. It followed that no clear legal procedure for the succession could exist, only precedents whose elements could be juggled as circumstances dictated. The army, the Senate, the family, the dead emperor all had their say, and important men such as Macro could therefore seize on the moment of confusion at the death of an emperor to impose their own choice. One wonders if the Senate, given a free choice, would actually have chosen Gaius – one rather hopes not – but the point is that they did not get the opportunity to choose.

Having thus cleverly achieved power, Gaius then proceeded to make himself so generally disliked that plots to kill him swirled around the court almost from his arrival in Rome. One of the elements in the conspiratorial atmosphere must have been a feeling that Gaius’ accession was less than legitimate. He might have received the necessary powers, been the apparent choice of the previous emperor, and been accepted by the various acclamations, but he had no government experience of any kind before becoming emperor (at the age of 25) and he was almost wholly unknown, except by name, to most of the senatorial class. While Tiberius had gone out of his way in the early years of his reign to respect the Senate and in his later years had at least made a show of keeping the senators informed about events, Gaius had no real conception of the importance of this attitude. The sequence of events at his accession, where the Senate’s role came last, will have confirmed that ignorance. He did make early gestures of respect towards the Senate, but this attentiveness did not last. So, to a sense that he had somehow become their ruler in part illegitimately was added the spectacle of a man who disdained the Senate, and who believed that he was an autocrat. In this belief he was, of course, quite correct, but in Rome at that time to act as an autocrat was politically inept.

His murder, after a reign of less than four years, was therefore not at all unwelcome. He had alienated the soldiers by ludicrous and insulting behaviour during the supposed preparation for the invasion of Britain, where he abandoned the expedition and instead ordered the army to pick up seashells; he was so careless as to repeatedly insult in public a member of his own Guard, Cassius Chaerea. Chaerea, increasingly annoyed at the emperor’s insults, sensed the atmosphere of disgust and contempt that had developed and of which Gaius was apparently unaware; who would dare tell him? After discussing it with others of the Guard, he killed the emperor in a public corridor at the games.13 This was not, therefore, quite so spontaneous an act as it might have seemed, nor was it merely an act of pique at being insulted. Behind Chaerea were not only some of his fellow Guardsmen, but others more highly-placed. He was actually the instrument of a full-blown conspiracy aimed at the emperor’s assassination.14

The conspiracy also involved a number of senators including C. Cassius Longinus, the brother-in-law of Gaius’ sister Drusilla, and M. Annius Vinicianus, a nephew of M. Vinicius, who was married to Gaius’ sister Julia Livilla. Both marriages had been arranged by Tiberius but, far from the wives sliding out of the political limelight because of their less than prominent husbands as had probably been intended, the husbands and their families had their political interests and ambitions sharpened and enhanced. Several other men were on the fringes of the plot, or had heard of it, and it is possible that Gaius’ uncle and nearest relative Claudius had also heard something. There were so many plots and rumours of plots in the year before the actual assassination that every senator would have known that something was going on, whether or not it was the truth. It seems likely that, even if Chaerea had failed to take action, or had failed in his plot, another plot would have succeeded. In fact, Chaerea only wounded the emperor; several other men immediately joined in, and he died from multiple wounds.

Gaius’ death was quickly followed by that of his wife and infant daughter, murdered by Guardsmen so that no focus of loyalty to him should survive, which is an interesting commentary on the force of heredity in Roman politics. Gaius’ German Guard, loyal even after death, hunted for the perpetrators for a time and killed some of them. The men soon calmed down when they saw the obvious confusion and distress of many of the people as they heard the news of the emperor’s death; he had not been unpopular with everyone, only among the powerful.

The main perpetrators had been Guardsmen, abetted by some senators, but as soon as the deed was done, this political alliance ended. The Guards searched the palace and found Claudius in hiding.15 This is portrayed at times as a fortuitous event, even a joke. Claudius had long been assumed to be so physically and mentally disabled as not to be considered as a successor, but it is more likely that he was the deliberate choice of the Guard, possibly in advance of the assassination, who would now want a new emperor to be of the imperial family, and a man who would be beholden to them, and so in their hands, as Macro had clearly intended Gaius to be.

The Senate met and debated what to do. There were the usual hopes among a few that the Republic could be revived, but this notion had no real support. Instead the debate centred, reasonably enough, on who should be the next emperor. It was apparently known that the Guard had control of Claudius, so he was one candidate. Two tribunes were sent to suggest that Claudius should pay heed to the Senate’s wishes rather than those of the Guardsmen, and to invite him to attend their meeting; he was, of course, a senator himself. Claudius sent a carefully neutral and diplomatic reply, saying that he was forcibly detained and could not attend the Senate. This may be thought to be a refusal to trust himself to the Senate out of fear, but it was certainly not a proclamation of himself as emperor. He and the Guard were theoretically leaving the decision to the Senate.

This all happened on the day of the murder. After a night to think things over, another meeting of the Senate took place, with probably no more than 100 senators present, though whether the missing men had fled or had not appeared because of fear or were simply not near enough to Rome to attend cannot be known. The meeting discussed the possible successors. The notion of a return to the Republic had now vanished. Apart from Claudius, already declared as a candidate, three others either put themselves forward or were suggested as possible emperors. All three were connected with the imperial family: M. Vinicius, the husband of Julia Livilla and so the dead man’s brother-in-law; Vinicius’ nephew, L. Annius Vinicianus; and D. Valerius Asiaticus, who was married to a sister of Gaius’ former wife Lollia Paullina, who had connections to several old noble families. All three of these men had probably been involved in the assassination plot. (For the connections of the candidates see Genealogical Table VI.)


It was, however, difficult to take any of these men, apart from Claudius, seriously as possible emperors. Claudius’ close family relationship to Gaius and Tiberius guaranteed him serious consideration. Asiaticus came from Narbonensian Gaul, the first from his province to become consul (in 35), but to the senators this was a clear bar to his candidacy; Vinicius, though a consul (in 30), was of small account and had been chosen by Tiberius as a husband for Julia Livilla for that very reason; his nephew Vinicianus may well not have been a fully declared candidate at all but may just have been Vinicius’ promoter (and heir). The absence of other candidates – there were surely senators who were fully capable of running the Empire, but who were simply not considered – shows that it was considered necessary that some sort of relationship with the imperial family was required for a man to be thought emperor material; capax imperii, as Tacitus put it. In that case, Claudius clearly had the edge. Asiaticus had another claim, however, for he had confronted a crowd outside the Senate House the day before. The crowd had been angry at the death of Gaius, who had retained a good deal of popular appeal. Asiaticus had successfully calmed them down, even though he had been asked if he was involved in the plot and had replied, ambiguously, that he wished he had been. In the Senate many may have seen him as a popular candidate with the implicit threat of a crowd storming the Senate in his favour.

Claudius was in the strongest position because he was much more clearly of the imperial family and because, after a night in the barracks of the Guard, he had made a good agreement with the Guardsmen. He was also careful to send respectful but firm messages to the Senate, promising good government if the Senate had accepted him but vengeance if not; the Guard would be quite capable of murdering the rump of senators who were still meeting. Only one-sixth of the 600 members were attending the meeting, so the Senate’s warning to Claudius the night before not to conduct a coup rang hollow; this was exactly what the Senate itself seemed to be doing.

In the end the Senate accepted him, and face was saved all round by his going in solemn procession, protected by the Guard, to the Senate House, where he was welcomed and invested with the imperial powers. At least the Senate could be sure that they had an emperor who was fully familiar with their proceedings and with the imperial system. Claudius had repeatedly asked Tiberius to be allowed to stand for office, but was always put off; then Gaius had made him consul with him in 37, and he was clearly an active politician, already well-known in Roman political circles, who cannot have taken too seriously the stories of his disability and unsuitability.16

Gaius had thus to a certain degree cleared the way for Claudius to succeed him. While he had not indicated any one man as a designated successor, not surprisingly since he was still in his 20s, he had removed at least two possible competitors. Ti. Gemellus, as was to be expected, did not survive the first year of Gaius’ rule, being killed around the end of 37, even though Gaius had formally adopted him with the implication that he was next in line.17 The second husband of Drusilla, Gaius’ sister, M. Aemilius Lepidus, was at one point, while the emperor was ill, in some way designated his heir. When Gaius recovered, Lepidus was a marked man; a designated successor had a vested interest in compassing an emperor’s death and he was killed in 39 as part of Gaius’ reply to a fairly widespread conspiracy designed to remove him.18 As a result only Claudius of the bloodlines of Augustus and Tiberius survived. If a hereditary succession was expected, he was the only possible heir to Gaius.

The succession system that Augustus had organized, which had worked with Tiberius and had been put under enormous strain by the accession of Gaius, had almost broken down under the impact of Gaius’ assassination. The system in part depended on the successor being publicly known and acknowledged by the ruler before the latter’s death. Gaius had at least been publicly assumed to be Tiberius’ heir, and had lived with him at Capri for six years, even if a formal designation had not been made. However, Gaius’ gestures towards nominating a successor, Ti. Gemellus and M. Lepidus, were both swiftly retracted. In the event, between them, the Guard and the Senate reached the conclusion that Claudius, Gaius’ nearest and almost only male relative, was the proper successor. The negotiations between them lasted only a day and a night, and, despite the assassins having had no candidate available before the murder, the crisis was effectively over within two days.19 So it could be claimed that, if one was an optimist, even in such an extreme case, the Augustan system had survived and had operated properly.

Of course, it had not. Neither Gaius nor Claudius had been properly trained for the office; both had been candidates of a faction within the Praetorian Guard; both had been foisted on the Senate, the rest of the army, and the Empire without consultation beyond the few Guardsmen at Misenum and in the barracks at Rome. The Senate, supposedly the real fount of power to whom Tiberius and Augustus had regularly expressed respect, had been sidelined in both cases. If the accession of Gaius had been in a disguised coup d’état, that of Claudius was a visible one. The one aspect of the Augustan scheme that had survived was that both men were members of the imperial family, and there seems to have been no question that candidates not from the family were universally excluded.

The accession of the new emperor did not, therefore, mean that Augustus’ scheme, now threadbare, would continue to survive much longer. Claudius was a man in his 50s whose disability made him ridiculous to some and an easy target for others. Vinicius, the other plausible candidate of 41, did not give up but apparently realized that he needed a figurehead of greater aristocratic stature than himself, such as his brother-in-law L. Arruntius Camillus Scribonianus (see Genealogical Table VI), who was now governor of Dalmatia. In 42 Scribonianus sent a message to the new emperor, ordering him to cease to rule and to lay down his offices. This quixotic opening of an intended coup presupposes two things: that Scribonianus believed that his command of the two legions in his province outweighed Claudius’ control of the Guard – and certainly his troops outnumbered the Guard, probably by at least two to one – and that the rest of the army would stand aside in the crisis: and, second, that he believed he had senatorial support. (It also indicated Scribonianus’ political naivety, of course.) It emerged that the trigger for the rising was a message sent to Scribonianus by L. Annius Vinicianus in Rome.20

Scribonianus certainly had wide senatorial connections, and M. Vinicius had been deeply implicated in the successful plot against Gaius the year before. Vinicianus had also either suggested his uncle as a candidate for emperor against Claudius’ candidature, or had suggested himself (or perhaps both). Between them these men clearly felt that their support in the Senate, combined with Scribonianus’ forces, would ensure success against Claudius and the Guard. It failed because they were wrong on both counts: Scribonianus’ two legions, except for a few officers, came out for Claudius, thus removing the ground on which he stood, and the Senate as a whole was hostile. After all, it was only a year since the Senate had deliberated and had accepted Claudius after a reasonable discussion, in which Vinicius and Vinicianus had been considered and rejected; there was no reason why the Senate as a whole should have changed its mind in the interval.

Scribonianus was an Arruntius by adoption only; his biological father was L. Furius Camillus. He was married to Vinicia, the sister of M. Vinicius and the aunt of Vinicianus. A comment attributed to Augustus, that his father L. Arruntius was a man capable of being emperor (capax imperii), may well have been the source of Scribonianus’ ambition. Vinicius’ marriage to Julia Livilla, and so his own association with the imperial family, fairly distant though it was, was presumably what made him put himself forward as an alternative to Claudius in 41. So if Vinicius had failed, maybe Scribonianus, with a descent a good deal older and more noble than either Vinicius or Claudius, might succeed.

The connections of the plotters suggest very strongly that it was high personal pride combined with their distant imperial connections that drove these men into their plots; quite probably it was the consciousness of his noble descent that was one of the main elements in Scribonianus’ attempted coup. It would not be the last time that such an attitude resulted in such an action. Also perhaps there was a perception that if a disabled character like Claudius could be made emperor, so could they. Scribonianus did have some support from the intransigent Republicans, but a revival of the Republic by this time was impossible, and Scribonianus aimed to be emperor, not to dismantle the imperial system.

Given such presuppositions, the pronunciamento of Scribonianus was by no means as hopeless as it now seems. He had the connections, the origins, the command of an army and the personal ambition which are all factors that were required; as a provincial governor he had the administrative and perhaps the military experience that both Gaius and Claudius lacked. If his legions had supported him he could have been a convincing candidate, but of course, it was a failure of his troops to go along with him – that is, that they were loyal to the Julio-Claudian dynasty and to the decisions of the Senate – which was the crucial matter. The disguised primacy of the army in the imperial succession was confirmed.

Claudius thus survived this challenge without difficulty, but he was the only member of the imperial family available and he was an elderly man. He had already been married three times. His son had died in an accident, and a daughter was also deceased; his other daughter Antonia was old enough to be married soon after he became emperor; and Claudius’ current wife, Messalina, gave birth to a son three weeks after the accession. He was named Tiberius Claudius Caesar Germanicus, later also called Britannicus. They also had a daughter, Octavia. Later, after Messalina’s disgrace, he married Agrippina (II), the former wife of L. Domitius Ahenobarbus and the daughter of his brother Germanicus; hence she was Claudius’ own niece. By then he was almost 60, but his new wife had a son of her own, L. Domitius Ahenobarbus, the later Emperor Nero. As a result, when Claudius died in 54, there were two male children in line to succeed (as when Tiberius died); of the two imperial daughters, Antonia was married to Cn. Pompeius Magnus who was killed in 47, and then to Faustus Cornelius Sulla Felix, though she apparently had no children by either husband; Octavia was married to her stepbrother Nero. Two male children: it was eerily reminiscent of the succession of Gaius.

In addition, there were more distant imperial family branches which, as Vinicius had shown, had to be taken into account. There was Rubellius Plautus, who was the son of Julia, Tiberius’ granddaughter. She had been married to Rubellius Blandus who, like Vinicius, had been assumed to be of no account, but as the imperial line thinned, any imperial descent became important. Then there was M. Junius Silanus and his two brothers, grandsons of another Julia, Augustus’ granddaughter. Also there was the family of M. Licinius Crassus Frugi, one of whose sons was the Pompeius Magnus who married Antonia in 41; he had three brothers. The family counted descent from the triumvir Pompeius and had great, even arrogant, family pride, though this only made them normal among the Roman nobility. However, to consider these men, Rubellius, the Crassi, the Junii, as part of the imperial family was only to emphasize the shortage of direct male heirs. The dynasty essentially depended, when Claudius died in 54, on his son Britannicus, aged 14, and his stepson Nero, aged 16.

Once again, as in 37, the succession was clear, though, also as in 37, there could have been competition from others. The two adolescent boys had equal claims. Nero was the older, a descendant of Augustus and of Octavia, and who had already given evidence of competence and intelligence; Britannicus was the biological son of the late emperor, descended in both parents from Octavia, but younger than Nero. This was not decisive since Nero was also Claudius’ son by adoption, and so the senior of the two by age. The decisive factor, in fact, was that Nero’s mother Agrippina was wholly determined that her son should rule, and it was she who organized the succession.

As Claudius died, Agrippina prevented Britannicus and his sisters from gaining access to their father, but contacted the Guard Commander, Sex. Afranius Burrus, who was clearly fully aware of what was going on and what was required. Burrus escorted Nero to the battalion of the Guard that was on duty, had him saluted as emperor, and then took him to the barracks. Nero made a short speech, promising rewards, and was acclaimed. He then went on to the Senate, where he was voted the imperial powers.21

The whole process might have been organized in advance, but it is clear that the pattern was that of Claudius’ accession rather than that of Tiberius or Gaius, and not only because Claudius, like Gaius, died at Rome. The prominence of the Guard is emphasized because the accession was, once again, in the nature of a coup d’état. Claudius’ will was suppressed (just as Tiberius’ had been), and Britannicus was deliberately kept in ignorance of what was going on. It is probable that Claudius intended the two boys to succeed jointly; it is certain that Agrippina was just as determined to see that Nero succeeded alone. In the event, the decisive factor was that Agrippina was alive and Claudius was dead.

Nero and his mother Agrippina were determined to rule. A preliminary move was the marriage of Nero with Octavia, his stepsister. Britannicus did not survive more than a year; he was too close to the throne, had as good an hereditary claim to it as Nero, and the court was, for the time being, under the control of Agrippina. Her earlier career had demonstrated a steely decisiveness that had brought her only son to the supreme position, and it will have been clear to her from the first that Britannicus could well be the ideal figurehead for an intriguing person of her own type. Some of the Guardsmen who first proclaimed Nero emperor are said to have asked where Britannicus was. So Britannicus inevitably went the way of Agrippa Postumus and Ti. Gemellus and Gaius’ infant daughter. By then the dynasty depended solely on Nero, and he and Octavia had no children.

This situation simultaneously weakened and strengthened Nero’s own position. The lack of an heir rendered plots and intrigues with the aim of assassinating him pointless, unless a non-imperial man was chosen, but no obvious candidate existed, or, while Nero lived, was likely to survive. The absence of any heir made Nero’s own person rather more valuable; if he died one possible result would be a civil war. The end of the Republic was in no-one’s actual memory now, but it was a well-worn historical topic of fear and horror. All aristocratic families had suffered in the civil war, and its horrors were fully understood. Yet for a dynasty to depend on a single life was clearly overall a source of weakness and might encourage the more distant family members to fancy their chances. The obvious parallel, for those with historical inclinations, was the situation among the Macedonians when Alexander the Great died: thirty years of civil warfare and the destruction of his Empire followed.

For a time this situation held its balance. During the ‘five good years’ the emperor’s imperial duties were essentially carried out by his mother; then, when he had contrived her death, by his former tutor and the chief of the Guard, Seneca and Burrus, in co-operation with the Senate. Nero’s assumption of sole power was indicated by the death or exile (or both) of Seneca and Burrus, and by his divorce of Octavia, closely followed by her murder. He married Poppaea, whose earlier husband, L. Salvius Otho, was despatched to govern Lusitania, as far from Rome as he could be sent. The imperial marriage produced a daughter. Yet, like every other emperor, Nero’s paranoia grew: threats, real and imagined, and possible competitors, real or imagined, were progressively eliminated. Poppaea was murdered while pregnant; their daughter died. All distant branches of the extended imperial family were affected: L. Junius Silanus, M. Licinius Crassus Frugi, Rubellius Plautus, C. Cassius Longinus, all of them died. M. Annius Vinicianus, son of the Vinicianus who plotted against Gaius and had been interested in the throne in 41, made another attempt and died. In the end there were no family members, near or distant, left. When Nero died, so did the dynasty.

It turned out that a distant threat was the most dangerous. An ancient sprig of the Republican nobility, the governor of Hispania Tarraconensis, P. Sulpicius Galba, mounted a challenge that was less easy to scotch than the conspiracies that were hatched or imagined at Rome. By that time it was no longer possible for Nero to select an heir. He could only do so from a member of the imperial family, and there were none left. Then Galba showed that this was not actually as important as it had seemed. The Senate, the real source of the opposition to him, was quite prepared to see the Julio-Claudian dynasty founded by Augustus eliminated.

This was the final failure of the system of organizing the succession set up by Augustus. The basic problem was that it was always capricious. Any emperor could, and should, nominate a successor, but there was no guarantee that the man chosen would reach the higher position for which he was intended; indeed, his very selection marked him for death. Of those selected, or assumed to be selected, to be the heirs of the five emperors of the Julio-Claudian family, three actually succeeded – Tiberius, Gaius and Nero – but perhaps ten or more did not (counting Agrippa Postumus and Ti. Gemellus as potentials). In this calculation Nero’s murderous paranoia was actually one of the least of the dangers; Augustus himself had been more lethal, though sometimes inadvertently. For, once a man had been chosen, he became immediately vulnerable. Plots and conspiracies seem to have been more or less continuous from the time of Augustus’ assumption of sole power to the death of Nero, but the dynastic failure was due mainly to the wear and tear of travel and work. The number of these men who died away from Rome, in carrying out the work of the emperor who could not leave the city, or could not go out to command an army, is instructive. They worked hard at times in dangerous places, and they fell ill, were wounded, became worn out and died.

In this, the normal mortality to be expected was assisted by the practice of intermarriage within the imperial family. It is a feature of the dynastic problem that so many of the emperors had so few children and this must in part be due to the insistence, begun by Augustus, on intermarriage, which perpetuated a degree of sterility evident all through the family, several of whose branches died out in the century of his dynasty’s reign. On top of this sterility, the murderousness of the emperors who apprehended and imagined plots against them greatly thinned the range of possible candidates.

The participation of the Senate in the process of succession and selection had turned out to be less important than that of the Guard, though Augustus, and at first Tiberius, had not intended that the Guard should be involved at all. The Guard’s importance increased with the imperial paranoia, and it did not take much to intimidate the Senate; a couple of judicial murders, perhaps a disappearance or two, a threat of a purge, were quite sufficient, especially if a senator could not know if he was next. After Gaius’ murder only a sixth of the senators turned up for the crisis debate on the succession. A fuller attendance would have been much more impressive and may well have intimidated, or at least impressed, even the Guard; it might also have led to a different result. Senatorial initiatives were stifled, including any that pushed for the selection of a successor or even suggested one, for this would be a move tantamount to betrayal, since any man nominated by anyone other than the emperor was immediately suspect.

At the same time the participation of the Senate in the inauguration of the new emperor was obviously vital. Tiberius had no need of the Senate’s approval for his assumption of the imperial office, having the requisite powers already, but he nevertheless sought and received it. This made it clear that this was a part of the process which was essential. Macro might bypass the Senate in announcing Gaius’ succession, but Gaius still had to go to the Senate to have those powers voted to him and, indeed, Macro’s early evasion of the Senate in announcing Gaius’ succession to the Empire was a backhanded tribute to its importance. Claudius required the approval of the Senate to become emperor; the Guard’s military muscle was not sufficient, and the situation was resolved by negotiation. The same was the case with Nero; the Guard acclaimed him, but it was the Senate that proclaimed him and voted him the necessary powers, and it was the Senate’s disapproval that eventually finished Nero off.

What Augustus had constructed was an autocracy that was effectively unbridled, though this was probably not his actual intention. Instead it seems clear he had been aiming at a partnership with the Senate, and that had also been Tiberius’ early intention, though he had become impatient with its servility towards him and its long-windedness. However, the actual power of the emperor proved to be without real restraints. The only restraint on an emperor’s actions was the Guard, which was scarcely concerned with legality or even with controlling an emperor’s madness or impulsiveness. Emperors could voluntarily exercise restraint, but some, such as Gaius and Nero, simply refused to do so, perhaps not even recognizing what it was. So, as with all autocracies, this meant that the only way of dealing with an emperor who refused all restraint was by assassination. In such a system it was opposition from within the imperial family that is the most potent, for the members of that family were the only ones who had the right to claim the throne, or indeed, had easy access to his person. Augustus had created, by his insistence on founding a dynasty, a toxic political system that regularly killed off those closest to the political fire. Had he been properly determined in making the Senate his partner in government, any dynastic succession would not have been considered; the Senate would then have chosen his successor, though whether they could ever have come to a peaceful choice is impossible to say. The potentialities, the lack of restraint and the sources of opposition were fully revealed by the career of Gaius, whose peculiar genius it was to appreciate fully what Augustus had produced.

Since the main danger to an emperor came from within his extended family, it followed that it was the members of that family who above all felt the full weight of his power. As a result the family, as a collective unit, in effect committed suicide, being the most obvious victim of Augustus’ work. The end result was a narrowing-down of the pool of potential rulers, first to one life, and finally into extinction. When eventually Nero lost his nerve and committed his assisted suicide, succession within the dynasty ceased to exist, but the system as Augustus had created it was left for the later emperors to live or die with.

Augustus’ system of finding a successor had been fatally flawed, since, without a legal and accepted system – a law, in fact – the only way of organizing a succession was by violence, implied or explicit, and by coups d’état. Only one imperial succession had actually worked as Augustus intended; the others were manipulated by the Guard or by courtiers and later ratified by the Senate, and two of the successions (at least) also involved the murder of the incumbent emperor. When the last of the emperors died without an heir of his family, the violence implied in the successions of Gaius, Claudius and Nero broke out. The civil war that followed was another of Augustus’ legacies to his Empire.

(NB: It is normal to refer to this set of emperors, from Julius Caesar to Nero, as the ‘Julio-Claudian dynasty’; in fact, this group does not constitute anything like a real dynasty but a set of five families, linked usually by marriage, but also by adoption: the Julii, the Claudii, the Domitii, the Pompeii and the Antonii. The irregularity of the several successions is demonstrated by the failure of any emperor to be succeeded by his biological son. On the other hand, discarding the term ‘dynasty’ seems impractical, for an accurate replacement can scarcely be found.)

If you find an error or have any questions, please email us at Thank you!