ca. A.D. 240-313
Roman emperor
Diocletian was one of Rome’s ablest emperors. His strong rule and dramatic reforms restored order to the Roman Empire after a century of crisis. His most significant change was the division of the vast empire into eastern and western regions, each with its own ruler. Diocletian himself took control of the eastern section, which shifted the empire’s power base from Rome to the east. During his reign, from A.D. 284 to 305, the outlying borders were once again made secure and the office of emperor regained its power.
Diocletian was born to a common family in Dalmatia, a province* east of the Adriatic Sea in modern-day Croatia. From his humble roots, he rose to command the bodyguard of the emperor Numerianus. After the assassination of Numerianus, the army proclaimed Diocletian emperor. He then defeated several rivals for the throne and become sole ruler of the empire in A.D. 286. He adopted the imperial* name Gaius Aurelius Valerius Diocletianus.
* province overseas area controlled by Rome
* imperial pertaining to an emperor or empire
Diocletian took command of the Roman Empire during an era of turmoil and decline. The economy suffered from rising inflation*, the border areas of the empire frequently came under attack from outside peoples, and the political system had fallen into chaos. During the century preceding Diocletian’s reign, the Senate had recognized 27 men as emperors, and many others had laid claim to the title. The majority of these rulers were murdered in office.
Diocletian decided that the empire was too vast to be ruled effectively by one person. To solve this problem, he decided to share his power with three others. He created a system in which each half of the empire, the east (consisting of Greece, Asia Minor, Syria, and Egypt) and the west (Italy, Gaul, Britain, and Spain) would be ruled by an emperor called an Augustus and a deputy called a Caesar. This arrangement—called a tetrarchy*— enabled the imperial leadership to function in four places at once. To assure an orderly succession, each Augustus was required to step down after ten years and to give his Caesar his place.
Diocletian, who kept the most authority, took control of the more prosperous eastern part of the empire and appointed his friend Maximian to rule the west. Together with their Caesars, the rulers subdued opposition within the empire and defeated the Persians and other invaders along the frontier. To secure the empire’s borders, Diocletian doubled the size of the Roman armies. He also tried to raise the prestige of the imperial throne by cultivating an aura of divine rule. He declared himself lord and god, donned a majestic purple robe and crown, and rarely appeared before his subjects.
Diocletian introduced several other administrative reforms. He reorganized the provinces into smaller units that were easier to manage. To curb inflation, he set price limits for a wide range of goods, including food and wine, and for the services of barbers and lawyers. He also imposed a more uniform tax system, established an annual budget, and changed the currency. While some of these policies failed, Diocletian’s reforms helped to revive the empire overall. However, he launched a brutal campaign of persecution* of Christians in A.D. 303, near the end of his reign, in a failed attempt to eliminate Christianity from his domain.
Having established order, Diocletian voluntarily retired after serving for 21 years. He forced Maximian to resign as well. Diocletian spent the rest of his days in a splendid palace at Salonae, in what is now the modern city of Split, Croatia. Despite his plan for an orderly succession, civil war erupted immediately after his retirement. Constantine I emerged from that war as ruler of the empire. (See also Barbarians; Byzantium; Economy, Roman; Government, Roman; Persian Empire; Rome, History of; Wars and Warfare, Roman.)
* inflation sharp increase in prices due to an increase in the amount of currency available
* tetrarchy rule by four people
* persecution organized and sometimes violent harassment of a group of people, usually because of their beliefs