This thesis uses philosophy of fiction to analyse episodic fictions in Vergil' s Aeneid. I argue that due to repeated lapses in the narrative framework, individual episodes seem to constitute deviant 'worlds' of their own, rather than incorporated insets. This fragmentation militates against the Aeneid's claims to a universalized totality. Chapter 1 uses ancient and modem theories of fiction to argue that mythical narratives are incomplete discourses lacking metalinguistic information about how they should be interpreted and made true. I propose that critical approaches seek to solve this anomaly by framing myths in new pragmatic structures. The question I pose is whether the Aeneid, in its incorporation of other narratives, propagates or corrects the pragmatic incompleteness of archaic material. To answer it I consider a series of adventitious fictions which test the narrative's incorporating frame. Chapter 2 concerns Aeneas and Sinon as inset narrators: are they just characters speaking or rival narrators creating their own separate worlds? Chapter 3 focuses on Book 3' s incorporation of the literary world of romance within the world of the Aeneid. I argue that Vergil moves away from paradox as mimetic representation of fantastical things, and embraces logical paradox. A prime example of the latter is Achaemenides, the traveller across fictional worlds. Chapter 4 is on the catabasis. It again accents metapoetry, arguing for Hades as a storehouse in which abstract fictions achieve embodied existence, while also detecting an equivalence between the changed realities of fiction and the changed realities of mystical experience. Chapter 5 considers ecphrasis as an incorporation of a rival representational world within the poem. I argue that the physical boundary separating artwork from narrative thematizes the boundaries, constantly lapsing, between Vergil's representational world and that of the rival artificer. Due to the lapses, the poem becomes an unframable multiplicity of contradictory worlds.