Marcus Antonius (Mark Antony), Caesar's co-consul, Gaius Octavianus (Octavian), Caesar's adopted son and great-nephew, and Marcus Lepidus, Caesar's magister equitum, formed an alliance. Known as the Second Triumvirate, they held powers that were nearly identical to the powers that Caesar had held under his constitution. As such, the Senate and assemblies remained powerless, even after Caesar had been assassinated. The conspirators were then defeated at the Battle of Philippi in 42. Although Brutus defeated Octavian, Antony defeated Cassius, who committed suicide. Brutus did likewise soon afterwards. Following Philippi, Rome's territories were divided between the triumvirs but the agreement was fragile and could not withstand internal jealousies and ambitions. Antony detested Octavian and spent most of his time in the East, while Lepidus favoured Antony but felt himself obscured by both his colleagues. Following the defeat of Sextus Pompeius, a dispute between Lepidus and Octavian regarding the allocation of lands broke out. Octavian accused Lepidus of usurping power in Sicily and of attempted rebellion and, in 36 BC, Lepidus was forced into exile in Circeii and stripped of all his offices except that of pontifex maximus. His former provinces were awarded to Octavian. Antony, meanwhile, married Caesar's lover, Cleopatra of Ptolemaic Egypt, intending to use the fabulously wealthy Egypt as a base to dominate Rome. The ambitious Octavian built a power base of patronage and then launched a campaign against Antony. Another civil war subsequently broke out between Octavian on one hand and Antony and Cleopatra on the other. This final civil war culminated in the latter's defeat at Actium in 31 BC; Octavian's forces would then chase Antony and Cleopatra to Alexandria, where they would both commit suicide in 30 BC. Octavian was granted a series of special powers including sole "imperium" within the city of Rome, permanent consular powers and credit for every Roman military victory, since all future generals were assumed to be acting under his command. In 27 Octavian was granted the use of the names "Augustus", indicating his primary status above all other Romans, "Princeps", which he used to refer to himself as in public, and he adopted the title "Imperator Caesar" making him the first Roman Emperor. Constitutional system The constitutional history of the Roman Republic began with the revolution which overthrew the monarchy in 509 BC, and ended with constitutional reforms that transformed the Republic into what would effectively be the Roman Empire, in