In the Early Modern Age, the theme of metamorphosis, inherited from classical Greco-Latin culture, appears in many fictional texts, in prose or verse, as well as in numerous works of art. In popular culture, metamorphosis never lost its vitality and appears in many tales of the oral tradition. However, while it fascinates and inspires countless artistic and literary manifestations, both cultured and popular, metamorphosis is strongly refuted by Christian dogma, which asserts, with great regularity, that it is impossible to change form. We will then analyse metamorphosis as a space that reveals some tensions, characteristic of the Early Modern Age. We will also consider what do these discourses about metamorphosis tell us about form: how do they conceive it? and to what extent, in discussing metamorphosis, do these discourses at the same time elaborate a reflection on form?