The aim of this thesis is to explore the relationship between Achilles Tatius' novel Leucippe and Cleitophon and the Platonic corpus. I have searched for Platonic allusions of various natures and purposes and grouped them into thematic chapters. I have also compared instances of similar uses of Plato in contemporary authors in order to classify both the individual cases and the place of Achilles Tatius' novel in its literary environment, including the intended readership. In my introduction I have argued that (...) through the combination in his works of philosophy and literary excellence Plato was an extremely important figure to the Greeks of the second sophistic. However, despite the increasingly influential opinion that Greek novel readership was not dissimilar to that of other works, the possibility that the Greek novelists used Plato in a more than cosmetic fashion has been relatively neglected. The uses of Plato on which I have concentrated are the employment of Platonic names as allusions to their namesakes; Platonic narrative technique as the model for the dialogue form and open-endedness of Leucippe and Cleitophon with the integration of this technique into the broader question of the discrepancies between the beginning and the end; the allusion to a particularly famous passage of the Phaedrus in the name of the heroine; the repeated allusions to the Phaedran flow of beauty, their purposes and the light they shed on the characterisation of Cleitophon; and the Phaedran scene-setting, indulged in by many other writers, which Achilles Tatius uses in two significant passages. The conclusions I have reached are that Achilles Tatius uses Plato far more extensively and imaginatively than hitherto realised; that such an intimate engagement can shed light on other issues, such as psychological characterisation and the question of humour; that Achilles Tatius wrote something of an "anti-Platonic" novel; and that his work displays many similarities with other works whose sophistication is less in doubt. (shrink)