Theodoric I (r. 418โ451) was the King of the Visigoths who completed the settlement of his people in Aquitaine (Gaul). Although he had conflicts with the Roman Empire over territory, he formed a crucial alliance with the Roman general Aetius when Attila the Hun invaded Gaul. At the Battle of the Catalaunian Plains in 451 AD, Theodoric led his cavalry charge but was killed in the chaos. His heroic death rallied his troops, who fought on to repel the Huns, marking one of the few defeats for Attila.