I demonstrate that Deleuze's identification of Aion as an empty form offers a fascinating model of temporality that prioritises variation. First, I suggest that Deleuze's identification of time as an empty form is supported by ancient Greek and Gnostic concepts of the relation of Aion and Chronos. From Plato, through Aristotle, to Plotinus the concept of time undergoes substantive revision, in the sense that temporal measurement becomes removed from the measurement of existent entities. This gradual untethering of time from movement gives rise to the development of the concept of eternity as an ontologically comprehensive mode of time that is devoid of content. It is here, with Deleuze's reading of the Platonic cosmology, that we see the first hints of the suggestion that Aion is involved with ontogenesis. Eternity is characterised as: a temporal ‘all’ that is non-reducible to the determinacy implied by any particular temporally localised existent or temporal series ; that which tends towards a diversity of possible states of affairs. Perhaps one of the most interesting aspects in the long history of Aion is that – in the ancient world – it was used in magical incantations. For the Gnostics and Oracles, Aion was a deity, and a potent one at that. From the Gnostic papyri, we get a vision of Aion as a force which enjoys eternal realisation. I suggest that the papyri conjure an image of Aion as a deity that is liberated from time, in the sense that it enjoys a neutrality with respect to the movements of any particular entity or group of entities – a form, in the most general sense of the term. Then, to clarify this mercurial aspect of an empty form of time, I elaborate on a complex analogy between Aion and Deleuze's concept of an ‘ideal game’ – an analogy that Deleuze specifies through reference to Fitzgerald and Borges. The claim is that Aion is an analogue of an ideal game in the sense that both share essential properties. Both Aion and the ideal game involve the multiplication of chance. Finally, I suggest that the differential aspects of Aion imply that it is pure variability; something which can be illustrated through a differential equation. These yield the suggestion that Aion enjoys realisation as an ontogenetic force. I further claim that ontogenetic forces may enjoy expression as the content of literature and mathematics. In concrete terms, temporality is involved in the creation of existent entities, which may be illustrated as various types of continuous multiplicity.