This article comments upon the episode of the dialogue between the Mytileneans and Pompey in Lucan's De Bello Civili (8,109-158) and its multiple poetic purposes are investigated. I argue that the episode in question has a significant structural value, since Lucan's emphasis on the islanders' loyalty and Pompey's reaction should be connected not only with the similar stance of the Lariseans in the previous book or the perfidy of the Egyptians later in the work, but also with many other passages and themes of the epic (as e.g. Caesar's greed, his presence at Amyclas' hut, the virtues of vetus Roma, the absence of an important tomb for Pompey). In this way the particular episode allows the poet to highlight tragic elements in Pompey's portrayal and more generally traits of his image that are in contrast with those of Caesar's, while at the same time facilitates Lucan's attempt to hint at his poetic immortality