Gnaeus Pompeius Magnus, known as Pompey the Great (106-48 BC), son of Pompeius Strabo, and one of the great military leaders of the late Roman Republic. He is of great importance in that his unconstitutional career provided many precedents for that of Octavian a generation later. Following his father's death, he threw in his lot with Sulla, raising a private army of three legions at his own expense.

After defeating Sulla's opponents in Sicily and Africa, Sulla allowed him a triumph 80 BC and given the surname Magnus ("the Great"), although he was not even a member of the senate.

He continued to serve the senatorial party after Sulla's death, defeated the Marian forces in Spain, and crushed remnants of Spartacus' slave revolt and he earned a second triumph. Although he was legally ineligible, Pompey demanded a consulship, and the assembly elected him consul for 70 BC, without having first been quaestor and praetor with Marcus Licinius Crassus as his colleague.

By now the Optimates were growing highly suspicious of Pompey, and the Senate did not vote him a normal proconsular province for 69 BC. However, in 67 BC a tribune, Gabinius, passed a law through the People, giving Pompey a command to clear the Mediterranean of pirates. This command was unprecedented, in that it gave Pompey authority greater than that of the governors in every province with a Mediterranean coast. Pompey destroyed the pirates in six weeks, conducting a vast sweeping operation from west to east.

The next year he was given unprecedented powers to subdue Mithridates VI of Pontus. Pompey took over the command held by Lucullus against Mithridates. Lucullus had been within sight of victory over Mithridates when his troops mutinied, and Pompey had no difficulty in completing the task. Pompey destroyed the Pontic army, and in the next four years he conquered eastern Asia Minor, Syria, and Jerusalem. His political settlements expanded Roman influence throughout the East.

In 62 BC he returned to Rome, celebrated a third triumph, rashly disbanded his army, and asked the Senate to ratify his eastern settlement, and grant land to his retiring veterans. Opposition to Pompey in the Senate was now strong (moreover he had divorced Mucia, forfeiting the support of the Metelli), and the Senate refused both these requests.

Pompey retaliated by joining Crassus and Julius Caesar in the First Triumvirate, a political alliance against the senate. He supported Caesar's candidature for the consulship of 59 BC, and in return Caesar succeeded in passing the legislation Pompey needed. To cement the alliance, Pompey married Caesar's daughter Julia.

The next ten years see Pompey in an awkward situation, but maintaining himself with great skill. In the Roman Republic of his day, it was easier to reach a position of eminence than to defend it against rivals. Pompey is sometimes criticised (and pitied) for allowing Caesar to build up his power, while being at a loss what to do himself; but there was little he could do to stop Caesar conquering Gaul.

In 57 BC he was put in charge of the corn supply for five years-an opportunity to improve his standing with the people of Rome.

Pompey agreed to renew the alliance in 56 B.C. After serving as consul with Crassus the next year, he received a five-year proconsulship to govern Spain. Defying Caesar, he ruled from Rome through legates. The death of Julia in 54 B.C. and of Crassus the next year further alienated Pompey and Caesar.

Civil disorders prevented elections in Rome, so the Senate made him sole consul in 52 BC, and allowed him to hold his provincial command in Spain for a further five years in absentia. By contrast, the Senate insisted that Caesar should resign his command before returning to stand as consul.

Caesar refused and crossed the Rubicon in 49 B.C.

The Senate looked to Pompey to defend the republic.

Leading the forces opposed to Julius Caesar in the civil war of 49-48 BC, Pompey eventually retreated to Greece and was defeated by Caesar at Pharsalus.

Had Pompey won the civil war, as he very nearly did, his position would have been that of Octavian 17 years later. As it was, he lost, fled to Egypt, where Ptolemy XIII ordered him killed to gain Caesar's favor. He died in Pelusium, Egypt, 48 B.C.