or Quintus Caepio Brutus born 85 died 42 BC, near Philippi, Macedonia Roman politician, leader of the conspirators who assassinated Julius Caesar in 44 BC. He joined Pompey's army against Caesar in the civil war (49) but was pardoned by Caesar after Pompey's death. He joined the plot to murder Caesar out of his desire to restore the Roman republic. After Caesar's death, he and Gaius Cassius formed an army in Macedonia; Brutus defeated the Caesarians under Octavian (Augustus) in the first engagement of the Battle of Philippi, but Mark Antony and Octavian crushed his army in a second encounter. Realizing the republican cause was lost, Brutus committed suicide