In 90 BC, Aquillius was sent as ambassador to Asia Minor to restore Nicomedes IV of Bithynia, who had recently been expelled from his kingdom by Mithridates VI of Pontus. However, after achieving this, Aquillius then encouraged Nicomedes to raid Pontic territory. This prompted a furious backlash from Mithridates in 89 BC, whose counter-attack began the First Mithridatic War.