Procopius of Caesarea (in Palestine) is the most important source for information about the reign of the emperor Justinian and his wife Theodora. From 527 to 531 Procopius was a counsel the great general of the time, Belisarius. He was on Belisarius's first Persian campaign, and later took part in an expedition against the Vandals. He was in Italy on the Gothic campaign until 540, after which he lived in Constantinople, since he describes the great plague of 542 in the capital. His life after that is largely unknown, although he was given the title illustris in 560 and in may have been prefect of Constantinople in 562-3. He wrote a number of official histories, including On the Wars in eight books, published 552, with an addition in 554, and On the Buildings in six books, published 561. He also left a "Secret History" , probably written c. 550 and published after his death, which was a massive attack on the character of Justinian and his wife Theodora. Parts are so vitriolic, not to say pornographic, that for some time translations from Greek were only available into Latin. The Secret History claims to provide explanations and additions that the author could not insert into his work on the Wars for fear of retribution from Justinian and Theodora. Since both before and afterward, Procopius wrote approvingly of the emperor, it was suggested in the past that he was not the author of the work, but it is now generally accepted that Procopius wrote it. Analysis of text, which show no contradictions in point of fact between the Secret History and the other works, as well a linguistic and grammatical analysis makes this a conclusive opinion.