On the death of his parents, Cato was brought up in the house of his uncle Marcus Livius Drusus (tribune in 91). He served in the ranks against the insurgent slave Spartacus in 72 and was military tribune in Macedonia (67) and quaestor (perhaps in 64) before obtaining a provincial appointment in Asia. As tribune-designate for 62, he incurred the resentment of Caesar by voting to execute the Catilinarian conspirators. Cato's opposition to Pompey, Caesar, and Marcus Licinius Crassus helped to bring about their coalition in the so-called First Triumvirate (60). With the Optimate Calpurnius Bibulus, Cato attempted unsuccessfully to obstruct Caesar's agrarian legislation. He was sent to annex Cyprus (58), but upon his return in 56 he continued to struggle against the Triumvirate.
Failing to obtain the consulship of 51, Cato had decided to retire from public life when civil war (Caesar against Pompey and the Optimates, 4945) broke out. Cato realized that the sole chance to preserve the republic lay in supporting Pompey, whom he had formerly opposed. He was entrusted with the defense of Sicily but found it impossible to hold the island and joined Pompey at Dyrrhachium. After Pompey's defeat at Pharsalus (in Thessaly), Cato led a small remnant of troops to Africa. He shut himself up in Utica, and even after the decisive defeat of the republican forces at Thapsus (46), he was determined to keep the gates closed until he had evacuated his adherents by sea. When the last transports had left, Cato committed suicide.
Although Cato was a doctrinaire and obstructionist politician, he provided the Optimates with relatively honest leadership in a corrupt age. His only surviving composition is a letter to Cicero (preserved in Cicero's Ad familiares, xv, 5). Immediately after his death Cato's character became the subject of debate. Cicero's panegyric Cato was answered by Caesar's bitter Anticato. In the Bellum civile by the poet Lucan (1st century AD), Cato is represented as a model of virtue. (Encyclopedia Britannica)
Great-grandson of Cato the Censor and a leader of the Optimates (conservative senatorial aristocracy) who tried to preserve the Roman Republic against power seekers, in particular Julius Caesar.