Metamorphoses

Metamorphoses was a book written by, obtained by Ezio Auditore da Firenze in the 16th century from one of Constantinople's many book shops.

Summary
''A classic piece of Latin narrative verse written sometime around 8 CE, "Metamorphoses" is an indispensable collection of fables based on Greek sources. One of the most widely read books of the Middle Ages, Ovid's masterpiece remains one of the major models for most of our modern conceptions of ancient Western mythology.''

Reference

 * Assassin's Creed: Revelations