Gnaeus Pompeius (ca. 75 BC – 12 April 45 BC), also known as Pompey the Younger (sometimes spelled Cneius, Gneius), was a Roman politician and general from the late Republic (1st century BC).
Gnaeus Pompeius was the elder son of Pompey the Great (Gnaeus Pompeius Magnus) by his third wife, Mucia Tertia. Both he and his younger brother Sextus Pompey grew up in the shadow of their father, one of Rome's best generals and not originally a conservative politician who drifted to the more traditional faction when Julius Caesar became a threat. When Caesar crossed the Rubicon in 49 BC, thus starting a civil war, Gnaeus followed his father in their escape to the East, as did most of the conservative senators. Pompey's army lost the Battle of Pharsalus in 48 BC, and Pompey himself had to run for his life, only to be murdered in Egypt on 29 September the same year.
After the murder, Gnaeus and his brother Sextus joined the resistance against Caesar in the Africa Province. Together with Metellus Scipio, Cato the Younger and other senators, they prepared to oppose Caesar and his army to the end. Caesar defeated Metellus Scipio and Cato, who subsequently committed suicide, at the Battle of Thapsus in 46 BC. Gnaeus escaped, this time to the Balearic Islands, where he joined Sextus. Together with Titus Labienus, former general in Caesar's army, the Pompey brothers crossed over to Hispania (the Iberian Peninsula, comprising modern Spain and Portugal), where they raised yet another army.