The First Triumvirate is the name most historians give to the political alliance between Gaius Julius Caesar, Marcus Licinius Crassus and Gnaeus Pompeius Magnus (Pompey). They made it in 60 BC to give each other power. Each person helped the others to be more powerful.
Caesar was able to gain money from Crassus to finance his public works campaign. He also gained military power from Pompey's loyal legions. Crassus, who was much envied and hated for his wealth and the means he used to attain it, was also able to gain popularity from Pompey as well as Caesar who had a loyal following in the plebeian class. Pompey was grateful to Caesar for his support against slander in the senate. Caesar's speeches in the senate were in favor of giving the newly conquered land to Pompey's returned legions. Pompey and Crassus ended their old grudge that dated back to the Third Servile War because they realised the advantages they allowed each other. To cement the Triumvirate, Crassus told Caesar's numerous debt holders that he would pay Caesar's loans if Caesar defaulted. Pompey married Caesar's only child, Julia. The Triumvirate lasted until Crassus' death in the Battle of Carrhae in 53 BC.
Caesar and Pompey started fighting. Caesar won at the Battle of Pharsalus. Caesar became dictator in the year 44 BC.