Gnaeus Pompeius Magnus, commonly known as Pompey /'pɑmpi/, Pompey the Great or Pompey the Triumvir (Classical Latin abbreviation: CN·POMPEIVS·CN·F·SEX·N·MAGNVS) (September 29 106 BC–September 28 48 BC), was a distinguished military and political leader of the late Roman Republic. Hailing from an Italian provincial background, after military triumphs he established a place for himself in the ranks of Roman nobility, and was granted the cognomen Magnus — the Great for his accomplishments.

Pompey was a rival of Marcus Licinius Crassus and at first an ally to Gaius Julius Caesar. The three politicians dominated the Late Roman republic through a political alliance called the First Triumvirate. After the death of Crassus (as well as Pompey's wife and Julius Caesar's only Roman child Julia), Pompey and Caesar became rivals, disputing the leadership of the Roman state in what is now called Caesar's civil war, an episode in the larger Roman Revolution which saw the death of the Roman Republic and the rise of the Emperors of Rome. Pompey fought on the side of the Optimates, the conservative faction in the Roman Senate, until he was defeated by Caesar. He then sought refuge in Egypt, where he was assassinated.

Early life and political debut

His father, Pompeius Strabo, was an extremely wealthy man from the Italian region of Picenum, but his family was not a part of the ancient families who had dominated Roman politics. Nevertheless, his father had climbed through the traditional cursus honorum, being quaestor in 104 BC, praetor in 92 BC and consul in 89 BC. However, despite his civil stature, Pompey's father was greatly disliked by the public. During Sulla's siege of the Colline Gate, which was lead by Strabo, the citizens of Rome blamed Magnus' father for the severe outbreaks of dysentry and other diseases. After his death, they hauled his naked body through the streets by meat hooks. Pompey had scarcely left school before he was summoned to serve under his father in the Social war. He fought under him in 89 BC against the Italians, at the age of seventeen. Fully involved in his father's military and political affairs, he would continue with his father until Strabo's death two years afterward. According to Plutarch, who was sympathetic to Pompey, he was very popular and considered a look-alike of Alexander the Great.

His father died in 87 BC, in the conflicts between Gaius Marius and Lucius Cornelius Sulla, leaving young Pompey in control of his family affairs and fortune. For the next few years, the Marian party had possession of Italy and Pompey, who adhered to the aristocratic party, was obliged to keep in the background. Returning to Rome, he was prosecuted for misappropriation of plunder but quickly acquitted. His acquittal was certainly helped by the fact that he was betrothed to the judge's daughter, Antistia. Pompey sided with Sulla after his return from Greece in 83 BC. Sulla was expecting trouble with Gnaeus Papirius Carbo's regime and found the 23-year-old Pompey and the three veteran legions very useful. When Pompey, displaying great military abilities in opposing the Marian generals who surrounded him, succeeded in joining Sulla via a cocktail of blackmail and arrogance, he was saluted by the latter with the title of Imperator. This political alliance boosted Pompey's career greatly and Sulla, now the Dictator in absolute control of the Roman world, persuaded Pompey to divorce his wife and marry his stepdaughter Aemilia Scaura, who was pregnant by her current husband, in order to bind his young ally more closely to him.