The Second Triumvirate was a political alliance formed after the Roman dictator Julius Caesar's assassination, comprising Caesar's adopted son Octavian (the future emperor Augustus) and the dictator's two most important supporters, Mark Antony and Marcus Aemilius Lepidus.
Octavian, the grandnephew and adopted son of Julius Caesar, had made himself a central military figure during the chaotic period following Caesar's assassination. In 43 BC at the age of twenty, he became one of the three members of the Second Triumvirate, a political alliance with Marcus Lepidus and Mark Antony.