First Triumvirate
The First Triumvirate was an unofficial political alliance known as an Amitica, between three prominent Roman politicians (triumvirs) which included
Julius Caesar, Pompey the Great and Marcus Licinius Crassus. "Pompey and Caesar now formed a pact, jointly swearing to oppose all legislation of which any one of them might disapprove. It lasted from approximately 59 BCE to Crassus' defeat by the Parthians in 53 BCE. The alliance was
"not at heart a union of those with the same political ideals and ambitions", but one where "all [were] seeking personal advantage."
Creation
Marcus Licinius Crassus and Gnaeus Pompey had been colleagues in the consulship in 70 BC, when they had legislated the full restoration of the tribunate of the people. However, since that time, the two men had entertained considerable antipathy for one another, each believing the other to have gone out of his way to increase his own reputation at his colleague's expense. Caesar contrived to reconcile the two men, and then combined their clout with his own to have himself elected consul in 59 BC; as Goldsworthy notes, "Caesar used persuasiveness and charm to convince the old enemies" that he could give them what they wanted if they both joined in supporting him. Caesar and Crassus were already allies, Crassus already having made "substantial loans" to Caesar, and he solidified his alliance with Pompey by giving him his daughter, Julia, in marriage. Each triumvir had their own reasons for joining together; per Goldsworthy, "Pompey wanted land for his veterans and ... ratification of his eastern settlement … Crassus... relief for the tax collectors of Asia… [Caesar] needed powerful backers if he was to achieve anything."