Galla Placidia, daughter of the Roman emperor Theodosius I, was a mother, tutor, and advisor to emperor Valentinian III, and a major force in Roman politics for most of her life. She was queen consort to Ataulf, king of the Visigoths from 414 until his death in 415, briefly empress consort to Constantius III in 421, and managed the government administration as a regent during the early reign of Valentinian III.