Middle Ages - Later Roman Empire

Later Roman Empire

The Roman Empire reached its greatest territorial extent during the 2nd century AD, with the following two centuries witnessing the slow decline of Roman control over its outlying territories. Economic issues, including inflation, and external pressures on the frontiers combined to make the 3rd century politically unstable, with a number of emperors coming to the throne only to be rapidly replaced by new usurpers. Military expenses increased steadily during the 3rd century, mainly in response to the need to defend against the renewed war with Sassanid Persia, which began in the middle of the 3rd century. The army doubled in size and various reforms in composition resulted in a new emphasis on cavalry and smaller units instead of the legion as the main tactical unit. The need for revenue led to increased taxes and a decline in numbers of the curial landowning class, and decreasing numbers of them willing to shoulder the burdens of holding office in their native towns. More bureaucrats were needed in the central administration to deal with the needs of the army, which led to complaints from civilians that there were more tax-collectors in the empire than tax-payers.

The Emperor Diocletian (r. 284–305) split the empire into separately administered eastern and western halves in 286; however, the empire was not considered divided by its inhabitants or rulers, as legal and administrative promulgations in one division were considered valid in the other. In 330, after a period of civil war, Constantine the Great (r. 306–337) refounded the city of Byzantium as the newly renamed eastern capital, Constantinople. Diocletian's reforms created a strong governmental bureaucracy, reformed taxation, and strengthened the army, which bought the empire time but did not completely resolve the problems it was facing: excessive taxation, a declining birthrate, and pressures on its frontiers amongst others. Civil war between rival emperors became common in the middle of the 4th century, diverting men from the empire's frontier forces and allowing the barbarians to encroach. But for much of the 4th century, Roman society had reached a new, stable form that differed from the earlier classical period in a number of significant ways - a widening gulf between the rich and poor as well as a decline in the vitality of the smaller towns. Another change was the conversion of the empire to Christianity, which occurred in a gradual process that lasted from the 2nd through the 5th centuries.

In 376, the Ostrogoths, fleeing from the Huns, received permission from the Roman emperor Valens (r. 364–378) to settle in the Roman province of Thracia. The settlement did not go smoothly, and when Roman officials mishandled the situation, the Ostrogoths began to raid and plunder Thracia. Valens, attempting to put down the disorder, was killed in battle with the Ostrogoths at the Battle of Adrianople on 9 August 378. Besides the barbarian threat from the north, internal divisions within the empire, especially within the Christian Church, caused troubles. In 400, the Visigoths invaded the Western Roman Empire and, although briefly forced back from Italy, in 410 they were able to sack the city of Rome. While the Visigoths were invading, in 406 the Alans, Vandals, and Suevi crossed into Gaul; over the next three years they spread across Gaul and in 409 crossed the Pyrenees Mountains into modern-day Spain. Other groups of barbarians took part in the movements of peoples in this time period. The Franks, Alemanni, and the Burgundians eventually all ended up in northern Gaul while the Angles, Saxons, and Jutes settled in Britain. In the 430s the Huns began invading the empire; their king Attila led invasions into the Balkans in 442 and 447, into Gaul in 451, and into Italy in 452. With Attila's death in 453, the Hunnic confederation he led fell apart. All of these invasions by the varied tribes totally rearranged the political and demographic face of what had been the Western Roman Empire.

By the end of the 5th century the western section of the empire was divided into smaller political units, ruled by the tribes that had invaded in the early part of the century. The last emperor of the west, Romulus Augustulus, was deposed in 476, which has led that year to be traditionally cited as the end of the Western Roman Empire. The Eastern Roman Empire, conventionally referred to as the "Byzantine Empire" after the fall of its western counterpart, had little ability to assert control over the lost western territories. Even though Byzantine emperors maintained a claim over the territory, and no barbarian king in the west dared to elevate himself to the position of Emperor of the West, Byzantine control of most of the West could not be sustained; the reconquest of the Italian peninsula and Mediterranean periphery by Justinian was the sole, and temporary, exception.