To one so necessarily preoccupied with maintaining her own position, tributary relations and military deployments could have been a distraction. Yet Wu Zetian was conscious of their importance to her legitimacy and far from neglectful; indeed, her half-century of managing the Chinese empire at its greatest but most vulnerable extent may constitute one of her most neglected achievements. In earlier times Han Wudi’s inner Asian empire had vanished into the desert within a matter of decades; but thanks in no small part to the empress, Tang Taizong’s would flourish for well over a century, opening up new perspectives for both the Middle Kingdom and its tribute-bearing satellites, while setting a benchmark against which subsequent Chinese dynasties, and then republics, would measure their success.
Heaven’s Sons – and Daughters – needed to look no further than the Mandate for the moral right to regulate the affairs of ‘All-under-Heaven’. The reverential relationships and tributary terms of such an imperium were by now well rehearsed and its structure generally understood as a concentric arrangement in which close subordination shaded into distant dependency. Like cartographic contours, the levels of submission rippled outwards from the emperor through the tightly controlled inner rings of the palace, the capital and the metropolitan hinterland, to the provinces, the frontier command areas, the vassal chiefs and tribes beyond, and so to the farthest-flung states on Heaven’s tribute-tendering horizon.
Only the methodology and the means for enforcing this ambitious arrangement left something to be desired. Confucian doctrine, formulated during the ‘Warring States’ era and partly in reaction to it, was adamant about civilian control over military affairs. It was one of the features that distinguished China’s culture from that of its nomadic neighbours. Though expansive and often downright aggressive, at few moments in history could the Chinese empire be characterised as militaristic. Military matters were traditionally treated as a subordinate function of the bureaucracy; under no circumstances should the bureaucracy become a subordinate function of the military. Theoretically, standing armies were anathema, professional soldiers parasites. Troops, whether conscripts or fubing(territorial militias), should be farmers-on-horseback and peasants-with-crossbows; generals should be, and usually were, bureaucrats-in-uniform. They were commissioned for a single campaign and, unless reappointed, reverted to civilian life after it. With military success offering a short cut to the highest office, a term disparaging an upstart as one who ‘went out a general and came in a chancellor’ (chu jiang ru xiang) gained wide currency.16
Military manoeuvres were ideally held during the slack season of the agricultural year, campaigns were kept to a matter of months, and expeditions were launched on a there-and-back basis with objectives clearly specified and minimal discretion allowed to the commander in the field. According to the Sunzi, the classic text on warfare of perhaps the fourth century BC, armies constituted ‘a way of deception’. Their well-drilled presence should serve to coerce and deter, but their actual use was to be discouraged. Far better to inveigle others into a multi-partite alliance and get them to do any fighting; hence the cliché, as old as China’s history, of ‘using barbarians to control barbarians’. For just as war, being notoriously unpredictable, was to be considered a last resort, so battle was to be offered only when victory was guaranteed. Indeed, if war represented a failure of diplomacy, then deployment represented a failure of strategy, and battle a failure of tactics.
It was not a question of ‘Confucian passivity’, nor, though the peoples of the steppe often interpreted it that way, of a sedentary and agrarian lifestyle being inimical to martial prowess. In his youth, the future Tang Taizong had been the very model of a warrior-prince and, latterly against Koguryo, one of the few emperors to accompany his troops into battle. Military discipline was strict, and when action was deemed necessary, vast imperial armies took the field and often inflicted colossal casualties. Given the ‘All-under-Heaven’ nature of the Mandate, any peoples in breach or ignorance of their obligations to the emperor were considered miscreants who must be induced to submit or be punished. In this sense, war was a corrective, an extension of the penal code from the recalcitrant individual (and his supposedly complicit family) to all those who dared defy the Heaven-ordained ruler, whether from within the frontier as ‘bandits’ (that is rebels) or from outside it as ‘barbarians’ (that is aliens).
In ancient times the carrot-and-stick of conventional strategy had worked well in cowing indigenous peoples like the Di, the Rong and the Man. Likewise the tribute-for-trade and peace-through-kinship compromises with the Xiongnu, Xianbei and Qiang had blunted the threat posed by the nomadic and generally unstable tribal confederations of the steppe. But as of the seventh century, the empire found itself confronted by more formidable foes – Turkic, Tibetan, Korean and Khitan – with their own cultural identities and political institutions, and with sedentary or semi-sedentarised populations at some remove from the Middle Kingdom.
Following the seven disastrous invasions of Korea by the Sui emperors and Tang Taizong, Wu Zetian’s 668 conquest of Koguryo smacked somewhat of face-saving. The Han empire’s Korean appendage had finally been reclaimed; protectorates were established in the peninsula; and of its three kingdoms, only that of Silla was left standing. But from an ally, Silla soon turned into a focus for resistance and then, with some Japanese assistance, into a determined enemy. As one imperial official had anticipated, ‘[The] dilemma was that, if the number of troops [sent to Korea] was small, China would be unable to exert enough force to retain control, but if the number was large, China would be exhausted trying to supply that force.’17 Korea was not a steppe-land from which the enemy could simply be driven off. Its proud and bounteous kingdoms proved as costly to hold as they had been to take. Some Koreans found service in the imperial forces, while large numbers of Koguryo’s farmers were transplanted west of the Yalu River into Manchuria and Hebei. But by 672 a process of Chinese retraction from the peninsula (Korean sources imply expulsion) was already under way. It culminated in the evacuation of Pyongyang in 676. Korea was not destined to form an integral part of the Chinese empire. Substantially reunited by Silla, it would acknowledge Tang suzerainty but retain full autonomy until, like China itself, it was overrun by the Mongols in the thirteenth century.
The empress had to console herself with a short-lived victory and a net territorial gain in what is now Liaoning province. As the protectorate of Andong (later Pinglu), this foothold in Manchuria with its residual claims on Korean allegiance and that of various Manchurian peoples would be echoed in the extreme south, where a protectorate based on what is now northern Vietnam continued to exercise tenuous claims over the adjacent kingdoms of south-east Asia. Both typified the adjustments, military and administrative, that characterised the organisation of the vastly extended Tang empire under Wu Zetian.
Of India in the eighteenth century it would be said that it ‘fell into Britannia’s lap while she was sleeping’. Less dozy, Tang Taizong had patiently positioned himself beneath the Turk qaghanates and then in the late 630s shaken their easternmost branch with a lunge into Mongolia and well-directed prods at the oasis-cities along the silk routes. But ultimately in Turkic Asia, as in Mughal India, the plums had fallen ripely, one dislodging others, with no laborious picking. Known as the On Oq (the ‘Ten Arrows’, or tribes), the various Turkic-speaking peoples who had comprised the Western Turk qaghanate succumbed in similar fashion during the 640s to fratricidal strife exacerbated by what one of their inscriptions describes as ‘the cunning and deceitfulness of the Chinese’; ‘the sons of the nobles became slaves of the Chinese’, it bemoans, ‘and their lady-like daughters became servants’.18 While the On Oq squabbled, their subject territories – rich city-states and any intervening pasturelands – had been gathered in and their allegiance transferred to the Heavenly qaghanate.
As witnessed by monk Xuanzang on his return journey through Xinjiang in 645, the harvest was substantial. All inner Asia was opened to Chinese penetration, and the so-called ‘Western Regions’ – an elastic term at the best of times – were stretched to their utmost. Under Tang Gaozong and Wu Zetian new protectorates were established over these frontier regions whose dependent territories sprawled in a great arc from Manchurian Andong on the Yellow Sea through what are now Outer Mongolia and eastern Kazakhstan to the deserts of Khorasan in north-eastern Persia/Iran. China’s empire would never again be so vast. On paper – itself a commodity symbolising both the novelty and fragility of the new imperium – Tang China was indeed ‘the greatest power in Asia at this time’.19
But it would be wrong to suppose that the frontier protectorates were subject to a level of control comparable to that in China’s domestic provinces and prefectures. Protectors-general exercised a theoretical command over vast areas, parts of which, such as those beyond the Pamirs or the Tian Shan, could be reached only by months of travel and might be quite inaccessible for long periods of the year. The protector-general was responsible for their pacification, but his role was as much supervisory as punitive, diplomatic as bureaucratic.
The term used for a protectorate’s far-flung components, whether prefectures or military commands, was jimi, meaning ‘control by loose rein’. Subordinate but autonomous, jimi territories were designated to fit within a military and administrative framework that satisfied imperial criteria, yet they were otherwise barely distinguishable from the political entities they replaced. The jimi prefects and commandants were themselves often non-Han, typically former rulers of the regions they controlled who had tendered their submission in return for recognition; their staff and military establishments were also substantially non-Han. They could be called on to assist in frontier defence, to dispatch or accompany tribute missions to the capital annually, and to lodge their sons there as security for their loyalty. The tribute might include some element of tax revenue, especially in respect of the settled and easily assessable oasis-states of Xinjiang. In return the jimi prefects enjoyed hereditary tenure and might receive titles, brides, revenue grants and food subventions from the imperial government, plus presents of greater value than those tendered as tribute.
The ‘loose rein’ chafed little, and least of all in peripheral regions like northern (i.e. Outer) Mongolia, Ferghana, Sogdiana and the trans-Pamir region, whose submission could only be described as nominal. Such tracts, so impressive on the map, would prove a liability. Conservatives like Wei Zheng, Tang Taizong’s crusty old adviser, had remonstrated vehemently against their inclusion and would not have been surprised at the ease with which some were about to be detached. As in Korea, Chinese ambivalence in military matters, and the ad hoc forces available for deployment, were woefully inadequate for maintaining an imperial colossus when challenged by other empire-builders.
The first of these challengers was Tibet. The amicable relations reached between Srong-brtsan-sgam-po and Tang Taizong had broken down around 660, the bone of contention being again the status of the Tuyuhun people in the treeless and boggy no man’s land that was Qinghai. By now, after various missions and a long stand-off over a Chinese envoy’s refusal to kowtow to the Tibetan king, the Tang should have realised that the Tibetans were not a mere confederation of nomadic tribes. An ambitious kingdom and would-be empire, Tibet had developed an integrated military, an effective administration and a literate culture based on its own grammar and script (an alphabetic one derived from a form of Sanskrit). The adoption of a distinctive and largely indigenous form of Buddhism (Vajrayana) was under way, metallurgical skills were highly developed, and Tibet’s mixed economy included artisans and traders as well as farmers and pastoralists.
Through the 660s the Tibetans pushed outwards, reclaiming the Tuyuhun lands in Qinghai and penetrating into both Sichuan and Xinjiang. In the last, they joined forces with disaffected local kingdoms and remnants of the Western Turk qaghanate to sever the southern Silk Road as used by monk Xuanzang. Then with the capture of Kuqa in 670 they virtually eliminated the Chinese presence throughout western Xinjiang and the Pamirs. The Tang retained control of the northern Silk Road from Turfan over the Tian Shan via what is now Urumqi to Ferghana, where a military base was established at Tokmak on the Issyk-kul. They also mounted a determined defence of the Gansu corridor against the Tibetans with a major expedition of 670 into Qinghai. This was heavily defeated, as was a repeat performance in 678. ‘I am afraid that the pacification of Tibet is not something that you can expect to accomplish between dawn and dusk,’ concluded an all-too-prescient submission to the imperial court of about this time.20
China’s two decades of domination in Qinghai and southern Xinjiang gave way to what has been called the first Tibetan empire. But Wu Zetian was far from reconciled to the situation. Though urged to write off what were called the ‘Four Garrisons’ (Tokmak, Kuqa, Kashgar and Khotan) of Anxi, the protectorate that corresponded to the Western Regions, she bided her time and in 692 in fact recovered them. Then she reinforced them. Thirty thousand troops were now permanently stationed in Anxi, with similar build-ups in other frontier protectorates. Against sustained and organised opposition, the traditional one-off, out-and-back ‘punitive’ expedition could no longer guarantee the security of the empire. Instead the frontier regions were to be policed by large permanent troop concentrations; and these, because of the difficulty of rotating soldiers so far from home, increasingly consisted of long-service recruits, both Han and non-Han, with a decidedly professional, even mercenary, approach to soldiering.
The empress had effectively buttressed Tang Taizong’s imperial construct but at some damage to both Confucian principles and centralised authority. For supplying and remunerating such garrisons would strain the economy and deplete the resources, military as well as financial, available at the centre. Worse, in the longer term these heavily militarised protectorates and provinces would prove as fractious as the peoples they were supposed to be controlling. In upgrading the defences of its extended frontiers against external attack, the dynasty exposed itself to attack from within its traditional frontiers. Even the great Tang Xuanzong would fail to resolve this dilemma and would eventually pay the price.
Nonetheless, Xinjiang and Ferghana had been safely restored to the fold. Not without interruption, they would continue under Tang supervision for another fifty years. Tibet, though, remained an enigma. When offering allegiance it often confused matters by demanding reciprocity, and when offering battle it often cheerfully proclaimed that it did so out of loyalty. As the seventh century drew to a close, succession disputes within the Tibetan leadership led to a lull in hostilities. It ended in 700 with resounding Chinese victories and a peace settlement that was thrashed out in the dying days of Wu Zetian’s reign. Sealed with a Chinese bride in 707, the terms of the settlement were vague but again implied an equality of status that future emperors would find intolerable.
Attacks and counter-attacks would continue along the length of the Tibeto-Tang frontier. Interminable and indeterminate, this zone ran all the way from the tousled hillsides beside the Mekong in Yunnan to the glacial gravel-beds of the upper Oxus in Afghanistan and the upper Jaxartes in Kyrghyzstan. The flashpoints were ever in the middle, where it brushed the Gansu corridor in Qinghai and veered towards Chang’an. But at its extremities the Tibetans were no less active and there found strange foes who quickly became staunch allies. In Yunnan these were the peoples of the emergent kingdom of Nanzhao, whose subsequent defiance of the Tang would destabilise the whole of south-west China including Vietnam. And in far Ferghana, the Tibetans’ new ally was even more formidable, he being Qutaiba bin Muslim, military governor of the now Ummayad province of Persian Khorasan.
Islam had arrived in central Asia within decades of the Prophet’s death. After rolling back Persia’s Sassanid empire much as Alexander of Macedon had its Achaemenid empire, the Arabs first briefly took the Sogdian city states of Bukhara and Samarkand in 708/9. At about the same time, Qutaiba bin Muslim’s counterpart in south Asia established an Arab bridgehead in India with the conquest of Sind in what is now Pakistan. Both initiatives were directed from Baghdad, headquarters of the Ummayad caliphate’s western viceroy.
The Chinese responded to the new presence by affording sanctuary to Pheroz (Firuz), a son of the last Sassanid ruler of Persia, and by encouraging their Western Turk jimi to resist the newcomers. But anything approaching a head-on clash between the two imperial juggernauts, the one triumphant throughout west Asia and the other throughout east Asia, failed to materialise. The Tang no more halted the Arab advance than did the Arabs the Tang advance. Both ground to a standstill in the political dust-storm stirred up by the Turks and Tibetans. When in 751 Arab and Tang forces did finally come face to face on the Talas River in Ferghana, the battle proved less bang than whimper. The victorious Arab and Tibetan forces failed to follow up their triumph, and the defeated Chinese had already written off Ferghana. World history was the only loser.
For the Tang, the Tibetan menace, though barely contained, had in fact been decisively overshadowed since as early as the 680s, when a greater threat emerged, or re-emerged, in the north. Though Tang Taizong had picked off the Eastern Turks of Mongolia in the 630s, in the early 680s they reformed under dynamic new leadership, repudiated their Tang protectoral status and, like a swarm returning to the hive, set up a Second Turk Qaghanate along the Orkhon River near what is now Ulan Bator in Outer Mongolia. From there they spilled across the Gobi, and with scant regard for either garrisons or walls, harried the Chinese provinces of Shanxi, Shaanxi and Ningxia. The new Eastern Turks demanded tribute-cum-trade plus the return of Turks who had been resettled within the empire; they undermined Wu Zetian’s authority by insisting their relationship was exclusively with the Tang emperor, not a Zhou empress; and like the Xiongnu of old, they commanded the supply of bloodstock on which the horse-loving Tang court, no less than its cavalry, had come to depend. They could not be ignored.
Exchanges, largely hostile but also commercial and diplomatic, dragged on for a quarter of a century. Under the great Qapaghan (Bag Chor, Mochuo, r. 695–716), the new qaghanate rivalled any of its predecessors, including that of Shanyu Maodun in Han times, and exacted enormous sums from the imperial exchequer as blood money. But any Turk plans for territorial enrichment at the expense of core China were held in check, partly by bolstered defence arrangements such as those introduced in Anxi and partly by the relentless pressure being experienced by the Turk qaghanate along its farther frontiers.
This pressure, though poorly understood by historians, would have been familiar enough to the Turks; it had powered their own eruption two centuries earlier. North-east Asia’s capacity for demographic upheaval was again making itself felt. As if spewing from ethnic geysers somewhere in the vicinity of where Siberia, Manchuria and Mongolia meet, a whole new generation of peripatetic peoples had begun herding its way into history.
Their names enter the records in the mid-seventh century, among the more familiar being Kyrgyz, Uighur and Khitan. They in turn would be followed by Jurchen, Mongol and Manchu. Like the Xiongnu and Xianbei, each attracted support from other ethnic groups to become composite peoples whose identity was dictated by the language group to which the leading clans belonged. And poorly differentiated at first, they would assume these distinct identities only as they entered the Chinese arena and steadily hijacked its history. Their impact can scarcely be exaggerated. By the thirteenth century a traveller like Marco Polo could genuinely suppose that ‘Cathay’, a name derived from ‘Khitan’ hegemony, was the appropriate designation for the Middle Kingdom, that its renaissance was down to Mongol rule, and that ‘khan’ (that is ‘qaghan’) as in ‘Kublai Khan’ was the normal title of its emperor. Fatimid Egypt as sampled by, say, a Frankish spice merchant would have been just as misleading, its Islamic present and Graeco-Roman past obscuring its pharaonic heritage.
Of the newcomers, the Kyrgyz, a Turkic-speaking people, would be the most peripheral; gravitating westward through and round Mongolia, they would play only a cameo role in the affairs of the Middle Kingdom. The Uighur, who also spoke a Turkic dialect, might have followed a similar trajectory; but as ferocious horsemen, they were sidetracked into contention for supremacy on the Mongolian steppe. Their presence attracted overtures from Wu Zetian in her tussle with the revived Eastern Turk qaghanate and began the long association between the Uighur and the Tang. As allies the Uighur would be of special assistance to Tang Xuanzong in his own tortuous dealings with the Eastern Turk qaghanate; and in 745, when the Turk qaghanate fell, it was the Uighurs who would succeed it in Mongolia with an essentially Uighur ‘Third Turk Qaghanate’. This would render even more crucial service to the Tang in their greatest hour of need, rescuing the dynasty while ravaging the empire on at least two occasions. The Third Qaghanate lasted nearly a century (745–840) before the Uighurs were finally dispersed, many of them resuming their westward drift to Xinjiang, where they would remain.
Rather different were the Khitan (Qidan). Their language has been called ‘proto-Mongol with Turkic borrowings’, and their cultural identity ‘Turko-Mongol’. How and where they acquired this pedigree, and what other than some vocabulary they shared with the later Mongols, is uncertain; but they had been known to the Chinese since the third century and by the seventh were established along the Manchuria–Mongolia border. In 648 Tang Taizong, pursuant to his abortive invasion of Korea, had secured their nominal allegiance. But in 695, when Wu Zetian had her hands full with the Tibetans and Qapaghan of the new Eastern Turks, they rose in unexpected revolt. Two imperial armies, one commanded by an impressive twenty-eight generals and the other reportedly consisting of 200,000 men, were rushed to the rescue only to be routed near where Beijing now stands. The Khitan then halted their advance and pitched camp in northern Hebei. In a reign replete with crises, this was possibly the greatest. Yet the empress, despite her years, handled it ‘with a calm and decision that were wholly admirable’.21 Qapaghan was bought off, in fact persuaded to lend his assistance against the Khitan; a determined effort was made to recruit more troops; and in 697/8 the Khitan were at last defeated. Though they withdrew, and after a dalliance as Turk allies accepted imperial suzerainty under Tang Xuanzong in 714, it was not the last that would be heard of them. The Khitan would remain an irritant for more than a century and then become major contenders for power in China itself in the tenth century.