Ammianus Marcellinus was a Roman soldier and historian who wrote the penultimate major historical account surviving from. The surviving books of his history cover the years 353 to 378.

His work, known as the Res Gestae, chronicled in Latin the history of Rome from the accession of the Emperor Nerva in 96 to the death of Valens at the Battle of Adrianople.

It is lauded as a clear, comprehensive, and generally impartial account of events by a contemporary.