Theodosius II, 401–50, Roman emperor of the East (408–50), son and successor of Arcadius. He preferred the study of theology and astronomy to public affairs, which he left to the guidance of his sister, Pulcheria—and, at times, to that of his wife Eudocia. The chief political events of his reign were the establishment (425) of Valentinian III as emperor in the West, the raids into the empire by the Huns under Attila, and the conferences held with Attila in regard to the ever-increasing tribute he demanded. In 431, Theodosius summoned the Council of Ephesus, which condemned Nestorianism, and in 449 he convoked and upheld the Robber Synod, which declared the orthodoxy of Eutychianism (see Eutyches). Among his other activities were the founding (425) of the higher school (or university) of Constantinople and the publication (438) of the Theodosian Code. His brother-in-law, Marcian, succeeded him.