Over the past two decades, scholars have devoted increasing attention to Roman civil war literature and its poetics, from the vocabulary of nefas, paradox, and hyperbole to the pervasive imagery of the state as a body violated by its citizens. Thebes and especially the civil war between Oedipus’ sons became prominent lenses through which Romans explored their country's strife-ridden past. Seneca's Phoenissae, however, has received comparatively little attention in this regard, often overshadowed by Statius’ epic Thebaid of the next generation. This paper investigates Seneca's contribution to the wider poetics of civil war through his expansion of the theme of incest, which Seneca uses to articulate civil war's most invasive, penetrative, and disintegrative effects. In particular, Seneca capitalizes on both the metaphorical potential of maternal violation and the eroticized imagery of Roman conquest to create disturbing points of contact between two generations of Jocasta's sons: the one who invaded her bed in the past, and the other who will soon invade his mother city. Seneca writes his Phoenissae to be an escalated return to the original sins of Oedipus’ incesta domus as another of Thebes’ native sons prepares to conquer his motherland.