In 527 Justinian became Emperor of the Eastern Roman [Byzantine] Empire, which had its capital at Constantinople. He succeeded his uncle Justin I to the throne more than 50 years after the Western Roman Empire, centered in Italy, had fallen to the Goths. Despite serious ongoing war with Persia on his eastern front, Justinian resolved to wrest the Italian peninsula from the usurping Goths.[Location map to be added here.]

He began his military adventures in the west in 533 by first attacking the Vandal Empire in North Africa. The Byzantine army, under the leadership of Justinian's favorite general, Belisarius, met quick success. In 535, perceiving that the Ostrogoth kingdom on the Italian mainland was weakened by internal dissension, Justinian launched a new invasion, first of Sicily and then into mainland Italy. Again the leadership was entrusted to Belisarius. In a five year campaign, Belisarius moved his forces northward through Naples and Rome, finally capturing the Ostrogoth king at Ravenna and once again bringing all of Italy under the rule of the Eastern Roman Empire. Belisarius returned to Constantinople in triumph.

The triumph, alas, was short-lived. As soon as Belisarius left, the Ostrogoths began reconquering the peninsula. Belisarius was dispatched to Italy again in 544. Despite having only a small and inadequate force, Belisarius kept the barbarians in check until 549, when he was withdrawn to Constantinople.