Marcus Junius Brutus was a Roman politician, orator, and the most famous of the assassins of Julius Caesar. After being adopted by a relative, he used the name Quintus Servilius Caepio Brutus, which was retained as his legal name. He is often referred to simply as Brutus.
Early in his political career, Brutus opposed Pompey, who was responsible for Brutus' father's death. He also was close to Caesar. However, Caesar's attempts to evade accountability in the law courts put him at greater odds with his opponents in the Roman elite and the senate. Brutus eventually came to oppose Caesar and sided with Pompey against Caesar's forces during the ensuing civil war (49–45 BC). Pompey was defeated at the Battle of Pharsalus in 48, after which Brutus surrendered to Caesar, who granted him amnesty.
With Caesar's increasingly monarchical and autocratic behaviour after the civil war, several senators who later called themselves liberatores (liberators) plotted to assassinate him. Brutus took a leading role in the assassination, which was carried out successfully on the Ides of March (15 March) of 44 BC.