Early life and political debut
Pompey was born in Picenum (modern Marche and the northern part of Abruzzo) to a local noble family. Pompey's father, Gnaeus Pompeius Strabo, was first of his family to achieve senatorial status, despite the anti-rural prejudice of the Roman Senate. The Romans referred to Strabo as a novus homo (new man). Pompeius Strabo ascended the traditional cursus honorum, becoming quaestor in 104 BC, praetor in 92 BC and consul in 89 BC. He acquired a reputation for greed, political double-dealing and military ruthlessness. He fought the Social War (91–88 BC) against Rome's Italian allies. He supported Sulla, who belonged to the optimates, the pro-aristocracy faction, against Marius, who belonged to the populares (in favour of the people), in Sulla's first civil war (88–87 BC). He died during the siege of Rome by the Marians, in 87 BC—either as a casualty of an epidemic, or by having been struck by lightning. His twenty-year-old son Pompey inherited his estates, and the loyalty of his legions.
Roman statue of so-called Pompey, at the Villa Arconati a Castellazzo di Bollate (Milan, Italy). It was brought there from Rome in 1627 by Galeazzo Arconati.
Pompey had served two years under his father's command, and had participated in the final part of the Social War. When his father died, Pompey was put on trial due to accusations that his father stole public property. As his father's heir, Pompey could be held to account. He discovered that the theft was committed by one of his father's freedmen. Following his preliminary bouts with his accuser, the judge took a liking to Pompey and offered his daughter Antistia in marriage. Pompey was acquitted.
Another civil war broke out between the Marians and Sulla in 83–82 BC. The Marians had previously taken over Rome while Sulla was fighting the First Mithridatic War (89–85 BC) against Mithridates VI of Pontus in Greece. In 83 BC, Sulla returned from that war, landing in Brundisium (Brindisi) in southern Italy. Pompey raised three legions in Picenum to support Sulla's march on Rome against the Marian regime of Gnaeus Papirius Carbo and Gaius Marius the Younger. Cassius Dio described Pompey's troop levy as a "small band".
Sulla defeated the Marians and was appointed as Dictator. He admired Pompey's qualities and thought that he was useful for the administration of his affairs. He and his wife, Metella, persuaded Pompey to divorce Antistia and marry Sulla's stepdaughter Aemilia Scaura. Plutarch commented that the marriage was "characteristic of a tyranny, and benefitted the needs of Sulla rather than the nature and habits of Pompey, Aemilia being given to him in marriage when she was with child by another man." Antistia had recently lost both her parents. Pompey accepted, but "Aemilia had scarcely entered Pompey's house before she succumbed to the pains of childbirth." Pompey later married Mucia Tertia. We have no record of when this took place. The sources only mentioned Pompey divorcing her. Plutarch wrote that Pompey dismissed with contempt a report that she had had an affair while he was fighting in the Third Mithridatic War between and 66 BC and 63 BC. However, on his journey back to Rome he examined the evidence more carefully and filed for divorce. Cicero wrote that the divorce was strongly approved. Cassius Dio wrote that she was the sister of Quintus Caecilius Metellus Celer and that Metellus Celer was angry because he had divorced her despite having had children by her. Pompey and Mucia had three children: The eldest, Gnaeus Pompey (Pompey the Younger), Pompeia Magna, a daughter, and Sextus Pompey, the younger son. Cassius Dio wrote that Marcus Scaurus was Sextus’ half-brother on his mother's side. He was condemned to death, but later released for the sake of his mother Mucia.