Ammianus Marcellinus composed a history of the Roman empire from 96 AD to 378 AD, focusing on the mid-fourth century during which he served in the army. His experience as a soldier during this period provides crucial realia of warfare, while his knowledge of literature, especially the genre of historiography, enabled him to imbue his narrative with literary flair. This book explores the tension between Ammianus’ roles as soldier and author, examining how his military experience affected his history, and conversely how his knowledge of literature affected his descriptions of the Roman army.