Tags: Monarch.
For other figures with this name see Gratian (disambiguation).Gratian (/ˈɡreɪʃən/; Latin: Flavius Gratianus Augustus; 18 April/23 May 359 – 25 August 383) was Roman emperor from 375 to 383.The eldest son of Valentinian I during his youth Gratian accompanied his father on several campaigns along the Rhine and Danube frontiers. Upon the death of Valentinian in 375 Gratian’s brother Valentinian II was declared emperor by his father’s soldiers.