Trebonianus Gallus was born in Italy to a family with a respected Etruscan senatorial ancestry. He was the governor of Moesia Inferior at the time that the emperor Trajan Decius and his son were defeated and killed there by invading Goths. It was alleged that Gallus had conspired with the Goths and was in some part to blame for this Roman defeat. Despite this rumor he was proclaimed emperor. Trouble on the frontiers and his inability to win the confidence of the army brought about a successful revolt by the future emperor Aemillianus, in which he was killed.