Ammianus Marcellinus

Ammianus Marcellinus, occasionally anglicized as Ammian (Ἀμμιανὸς Μαρκελλῖνος; c. 330 – c. 391 – 400), was a Roman soldier and historian who wrote the penultimate major historical account surviving from antiquity (preceding Procopius). Written in Latin and known as the Res gestae, his work chronicled the history of Rome from the accession of Emperor Nerva in 96 to the death of Valens at the Battle of Adrianople in 378. Only the sections covering the period 353 to 378 survive.

Notable works: Roman History

Source: Wikipedia — https://en.wikipedia.org/wiki/Ammianus_Marcellinus