Book 8 of Lucan's Bellum Civile opens with Pompey in desperate flight from Caesar after the disaster of Pharsalus, and in equally desperate search for a reliable ally. Before the fateful decision is taken that Pompey should make for Egypt, where he will be murdered upon arrival by minions of the treacherous Ptolemy XIII, Pompey dispatches his Galatian client-tetrarch Deiotarus to sound out the distant Parthians and summon their armed hordes to wage war on his behalf ; the king promptly (...) embarks on his arduous errand, never to reappear in Lucan's text. Although Pompey is said by several historical sources to have expressed an interest in exploring the prospect of an alliance with Parthia, the mission of Deiotarus is almost certainly a complete fiction, as Duff has convincingly demonstrated. What could Lucan's motive have been for inventing this episode out of whole cloth? (shrink)