The first triumvirate, formed in 60 BCE, consisted of Julius Caesar, Pompey, and Crassus, and it was an informal political alliance. It aimed to consolidate their power in Rome but lacked an official legal framework. In contrast, the second triumvirate, established in 43 BCE, included Octavian (later known as Augustus), Mark Antony, and Marcus Lepidus, and it was a formal political arrangement authorized by the Senate. The second triumvirate was primarily created to seek vengeance against the assassins of Julius Caesar and govern Rome, with defined powers and responsibilities.