information:extraction, quality:correction, structural:reformatting
Sources and models

Ovid's relation to the Hellenistic poets was similar to the attitude of the Hellenistic poets themselves to their predecessors: he demonstrated that he had read their versions... but that he could still treat the myths in his own way.

— Karl Galinsky

Ovid's decision to make myth the primary subject of the Metamorphoses was influenced by Alexandrian poetry. In that tradition myth functioned as a vehicle for moral reflection or insight, yet Ovid approached it as an "object of play and artful manipulation". The model for a collection of metamorphosis myths was found in the metamorphosis poetry of the Hellenistic tradition, which is first represented by Boios ' Ornithogonia —a now- fragmentary poem of collected myths about the metamorphoses of humans into birds.

There are three examples of Metamorphoses by later Hellenistic writers, but little is known of their contents. The Heteroioumena by Nicander of Colophon is better known, and clearly an influence on the poem: 21 of the stories from this work are treated in the Metamorphoses. However, in a way that was typical for writers of the period, Ovid diverged significantly from his models. The Metamorphoses was longer than any previous collection of metamorphosis myths (Nicander's work consisted of probably four or five books) and positioned itself within a historical framework.

Some of the Metamorphoses derives from earlier literary and poetic treatment of the same myths. This material was of varying quality and comprehensiveness; while some of it was "finely worked", in other cases Ovid may have been working from limited material. In the case of an oft-used myth such as that of Io in Book I, which was the subject of literary adaptation as early as the 5th century BCE, and as recently as a generation prior to his own, Ovid reorganises and innovates existing material in order to foreground his favoured topics and to embody the key themes of the Metamorphoses.