Theodosius II, the only son of Emperor Arcadius and Aelia Eudoxia, was raised to the rank of Augustus at only nine months old. His mother died in 404 and his father in 408 leaving him sole emperor at six. His sister, Aelia Pulcheria, was given responsibility for his education, and the title of Augusta in 414. Most of his reign was long and peaceful, the most notable events being the completion of a new legal code, Codex Theodosianus, and the fortification of Constantinople, making it one of the most heavily defended locations in history. The last years of his reign were marred by repeated invasion of the Balkans by the Huns led by Attila. Theodosius died after a serious hunting accident in 450 A.D.