Throughout the period following the Punic Wars, which finally came to an end in 146 b.c.e., the Roman Republic was embroiled in almost constant warfare. This included struggles against local rebellious tribes, such as in Spain, and especially internecine warfare between various factions in Rome itself. These conflicts were both the cause and result of the fact that the Senate granted generals, usually powerful politicians, the right to lead their own quasi-personal forces in the field. Ambitious men could then use these forces to advance their own political aims. Wars against Germanic tribes, Iberian guerrillas, and Parthian warriors, some successful, some not, had the effect of exhausting the treasuries of the Republic.
In this atmosphere, where powerful men controlled essentially forces of henchmen to enforce their will, Julius Caesar rose to power. Achieving prominence through his military successes, a time-honored formula, he turned on Pompey, an old ally, defeated him in a civil war, and essentially altered the laws of the Republic to grant him an almost unchecked degree of authority. His murder sparked a civil war that culminated in his nephew Octavian's defeat of his former ally Antony at the Battle of Actium. The result of this complex series of events, all undergirded by extreme social dislocation and strife, was that Octavian granted himself the title of Emperor. The Republic thus came to an end.