This paper argues that Ovid was familiar with the philosophy of the Hellenistic dialectician Diodorus Cronus, in particular, his views on fate, which he probably knew from Cicero’s De Fato, and the so-called “horned” and “veiled” arguments associated with him. Ovid draws on these aspects of Diodorus’ philosophy to tell the story of Cipus in Metamorphoses 15 ; he uses them to portray Cipus’ attempt to avoid kingship as a highly ambiguous and unnecessarily risky, if not self-defeating, exercise in forestalling fate and thus leaves open the question of whether Cipus, in the end, succeeds in his attempt. This reading complements others that have argued that the inescapability of kingship, not Cipus’ moral choice, is the central point of the story. It also adds to our appreciation of Ovid’s use of philosophical material in his epic, an area of growing interest in Ovidian studies, which has thus far paid no attention to Diodorus Cronus and only a little to the influence of Cicero’s philosophical works.