Procopius of Caesarea (in Palestine) [born c.490/507- died c.560s] is the most important source for information about the reign of the emperor Justinian [born 482/3, ruled. 527-565] and his wife Theodora [d. 547/8]. From 527 to 531 Procopius was a counsel the great general of the time, Belisarius [505-565]. He was on Belisarius's first Persian campaign [527-531], and later took part in an expedition against the Vandals [533-534].