Leo I, Emperor of the East, -474

Leo I (Ancient Greek: Λέων, romanized: Leōn; c. 401 – 18 January 474), also known as the Thracian (Latin: Thrax; Ancient Greek: ὁ Θρᾷξ), was Eastern Roman emperor from 457 to 474. He was a native of Dacia Aureliana near historic Thrace. He is sometimes surnamed with the epithet the Great (Latin: Magnus; Ancient Greek: ὁ Μέγας), probably to distinguish him from his young grandson and co-augustus Leo II (Ancient Greek: ὁ Μικρός, romanized: ho Mikrós, lit. 'the Small'). During his 17-year rule, he oversaw a number of ambitious political and military plans, aimed mostly at aiding the faltering Western Roman Empire and recovering its former territories. He is notable for being the first Eastern Emperor to legislate in Koine Greek rather than Late Latin. He is commemorated as a saint in the Eastern Orthodox Church, with his feast day on 20 January.