Procopius was with Belisarius on the eastern front until Belisarius, after his defeat at Callinicum[?] in A.D. 531, was recalled to Constantinople. Procopius witnessed the Nika riots of January, 532, which Belisarius and his fellow general Mundo[?] repressed with a massacre in the Hippodrome. In 533, he accompanied Belisarius on his victorious expedition against the Vandal kingdom in North Africa, took part in the capture of Carthage, and remained in Africa with Belisarius' successor Solomon[?] when Belisarius returned to Constantinople. But he rejoined Belisarius for his campaign against the Ostrogothic kingdom in Italy and experienced the Gothic siege of Rome that lasted a year and nine days, ending in mid-March, 538. He witnessed Belisarius' entry into the Gothic capital, Ravenna, in 540. Thereafter his relationship with Belisarius seems to have cooled. Belisarius was sent back to Italy in 544 to cope with a renewal of the war with the Goths, now led by an able king named Baduila, as he calls himself on his coins, or Totila, as Procopius calls him. Procopius appears to have no longer been on Belisarius' staff.
The first seven books of his History of Justinian's Wars, which were published as a unit, seem to have been largely completed by 545, but were updated to mid-century before publication, for the latest event mentioned belongs to early 551. Later, Procopius added an eighth book which brings the history to 552, when a Byzantine army led by the eunuch Narses finally destroyed the Ostrogothic kingdom. The first book of Procopius' De Aedificiis ("On Buildings") a laudatory description of Justinian's building activity in the empire, must date to before the collapse of the first dome of Hagia Sophia in 557, but the remaining books seem to have been added later and the work may be unfinished. The Secret History was discovered centuries later in the Vatican Library and published in 1623, but its existence was already known from the Suda, which referred to it as the Anekdota ("the unpublished composition"). The Secret History covers the same years as the seven books of the History of Justinian's Wars and purports to have been written after they were published. The view that is generally accepted dates its composition to 550.
The Secret History reveals a man who had become deeply disillusioned with the emperor Justinian and his wife, Theodora, as well as Belisarius, his old commander, and Antonina, Belisarius' wife. The De Aedificiis tells us nothing further about Belisarius but it takes a sharply different attitude towards Justinian. He is presented as a caring emperor who built churches for the glory of God and defenses for the safety of his subjects and who showed particular concern for the water supply. Theodora, who was dead when this panegyric was written, is mentioned only briefly but Procopius' praise of her beauty is fulsome. The panegyric was likely written at Justinian's behest, however, and we may doubt if its sentiments are sincere. We do not know when Procopius himself died but in 562 there was an urban prefect of Constantinople who happened to be called "Procopius". In that year, Belisarius was implicated in a conspiracy and was brought before this urban prefect. There is no solid evidence to identify the prefect with the historian but readers of the Secret History's indictment of Belisarius must wonder if the irony of history arranged this final encounter between Procopius and his erstwhile commander.
Procopius belongs to the school of secular historians who continued the traditions of the Second Sophistic[?]; they wrote in Attic Greek, their models were Herodotus and especially Thucydides, and their subject matter was secular history. They avoided vocabulary unknown to Attic Greek and would insert an explanation when they had to use contemporary words. Thus Procopius explains to his readers that ekklesia, meaning a Christian church, is the equivalent of a temple or shrine[?] and that monks are "the most temperate of Christians...whom men are accustomed to call monks." (Wars 2.9.14; 1.7.22) In classical Athens, monks were unknown and an ekklesia was the assembly of Athenian citizens which passed the laws. The secular historians eschewed the history of the Christian church, which they left to ecclesiastical history--a genre that was founded by Eusebius of Caesarea. In fact, Procopius excludes Christianity from his work so resolutely that Edward Gibbon considered him a pagan, but that view is no longer held. He indicated (Secret History 26.18) that he planned to write an ecclesiastical history himself and, if he had, he would probably have followed the rules of that genre. But, as far as we know, the ecclesiastical history remained unwritten.
A historical novel based on Procopius' works (along with other sources), Count Belisarius, was written by noted classical scholar Robert Graves in 1938.