The period of Justinian's reign (527-565)
  Justinian's long reign saw a series of military campaigns at both extremes of the empire, aiming to recover the west from the Goths and defend the east from the Persians. The Vandal kingdom of North Africa was conquered by general Belisarios in less than two years (532-534). In Italy, a first campaign by the same general (535-540) ended with the capture of Ravenna, the Ostrogothic capital. Between 542 and 552, Belisarios and Narses restored the Byzantine dominion in Italy. The conquest of Spain took place in 551 with the help of the Visigoth king himself. Finally, in 561, the Persian threat at the eastern frontier was dealt with by treaty for which the Byzantines payed annual tribute.
  Justinian's legal reforms included the consolidation of earlier codes and their pruning of obsolete and constradictory matter. The resulting Codex Justinianus, published in 529 (and again in 534), was supplemented by the Digesta (Pandektai), a fifty-volume collection of ancient law (533). Moreover, between 534 and 542, a series of edicts (Novellae), written in Greek, attempted to curb corruption, limit the powers of rich landowners, and revise the taxation system to meet the costs of expansion and reorganisation. Not all of Justinian's reforms were popular. His attempt to restrict the public sector met with civil protest, which culminated in the 532 Nika revolt and attempted usurpation by emperor Anastasios' relatives. For many days the rioters vandalized the capital, before they were bloodily suppressed inside the Hippodrome.
  Like most emperors since Constantine, Justinian was actively involved with ecclesiastical affairs, his policy being mainly one of reconciliation between orthodoxy and Monophysitism. He was also a significant patron of architecture, having ordered the construction and restoration of numerous churches, monasteries, palaces, fortifications, aqueducts, and other amenities, in both the capital and the provinces (for which Prokopios gives extensive accounts). When the Nika riot left a substantial part of Constantinople in ashes, Justinian replaced the old basilica of St Sophia by a magnificent new church (inaugurated in 537), a symbol to this day of the Justinianic era.
  The age of Justinian is justly regarded as the final stage of the old order before massive loss of territory and other calamities. The Great Plague of 542 killed hundreds of thousands throughout the empire, depriving the state of invaluable tax payers and soldiers. The costly territorial expansion further drained the financial ressources that were necessary to sustain its size and administration network. As a result, Justinian's vision was short-lived. His successors in the late sixth and early seventh centuries were unable to hold back the attacks that came from several fronts: the Persians moved into Syria, Palestine, and Egypt; much of Italy was once again lost, to the Lombards this time; Slavs and Avars invaded the Balkans. There was a brief recovery under Herakleios (610-641), whose campaigns against the Persians were ultimately successful, but by the seventh century the weakened empire was prey to the Arabs.