Gratian can refer to: Felinus and Gratian (d. 250 AD), Christian martyrs and saints Gratianus Funarius, Roman soldier, father of emperors Valentinian I and Valens Gratian, Roman emperor from 367 to 383 Gratian, a 5th-century Romano-British usurper and emperor Pope Gregory VI (died 1047), whose name was John Gratian before he assumed the papacy the author of the 12th-century Decretum Gratiani Gratian of Tours (Gatian), bishop of Tours