Gnaeus Pompeius Magnus (Latin: [ˈnːae̯.ʊs pɔmˈpɛjjʊs ˈmaŋnʊs]; 29 September 106 BC – 28 September 48 BC), known in English as Pompey or Pompey the Great, was a leading Roman general and statesman. He played a significant role in the transformation of Rome from republic to empire. He was (for a time) a student of Roman general Sulla as well as the political ally (and later enemy) of Julius Caesar.

A member of the senatorial nobility, Pompey entered into a military career while still young. He rose to prominence serving the dictator Sulla as a commander in the civil war of 83–82 BC. Pompey's success as a general while young enabled him to advance directly to his first Roman consulship without following the traditional cursus honorum (the required steps to advance in a political career). He was elected as Roman consul on three occasions. He celebrated three Roman triumphs, served as a commander in the Sertorian War, the Third Servile War, the Third Mithridatic War, and in various other military campaigns. Pompey's early success earned him the cognomen Magnus – "the Great" – after his boyhood hero Alexander the Great. His adversaries gave him the nickname adulescentulus carnifex ("teenage butcher") for his ruthlessness.In 60 BC, Pompey joined Crassus and Caesar in the military-political alliance known as the First Triumvirate. Pompey married Caesar's daughter, Julia, which helped secure this partnership. After the deaths of Crassus and Julia, Pompey became an ardent supporter of the political faction the optimates— a conservative faction of the Roman Senate. Pompey and Caesar then began contending for leadership of the Roman state in its entirety, eventually leading to Caesar's Civil War. Pompey was defeated at the Battle of Pharsalus in 48 BC, and he sought refuge in Ptolemaic Egypt, where he was assassinated in a plot by the courtiers of Ptolemy XIII.