Octavian Augustus, the first and possibly greatest Roman emperor, founded the Roman empire after defeating Mark Antony and Cleopatra. He reformed the coinage and the military, and embarked on a huge building program all across the empire. Augustus was succeeded by his stepson Tiberius after a long reign of 41 years. He was 77, having ruled from 27 B.C. to 14 A.D. Colosseum, Rome.