2. 509 B.C. Rome becomes a republic . 264 B.C. The First Punic War with Carthage begins . 218 B.C. In the Second Punic War, Hannibal invades Italy . 44 B.C. Conspirators kill Julius Caesar . A.D. 284 Diocletian, who will divide the Roman Empire, becomes emperor. A.D. 476 Western Roman Empire falls with the ouster of the last emperor, Romulus Augustulus . 500 B.C.