Procopius - History of the Wars, Books V. and VI.

Procopius lived from 500 to 565 in Eastern Rome. He is considered the last major ancient historian. The writings of Procopius are the primary source of information for the rule of the Roman emperor Justinian. Procopius was the author of a history in eight books of the wars fought by Justinian, a book on Justinian's public works, and a book called Secret History. The Secret History claims to be about scandals that could not be put in the published history books. The Gothic Wars are covered in the History of Wars.