Verg. Aen. 2.311–12 iam proximus ardet | Vcalegon. This striking phrase is twice echoed, as commentators observe. The burning neighbour Ucalegon reappears in Juv. 3.198–201 iam poscit aquam, iam friuola transfert | Vcalegon … | ultimus ardebit quem … . And the words proximus ardet reappear in Hor. Epist. 1.18.84 paries cum proximus ardet.
Fraenkel suggested that Virgil and Horace both echo the ending of a lost verse of Ennius (E. Fraenkel, Horace [Oxford, 1957], 319 n. 1). There is no need to invoke Ennius. Virgil is echoing Callim. Hymn 4.180 γείτονος αἰθομένοιο (itself echoing Hom. Il. 21.523 ἄστεος αἰθομένοιο), also in the context of an enemy incursion.