Music historiography generally describes opera seria as an archetypal genre built on two premises: role typology and the number and placement of arias. Approaches from the perspective of theatre scholarship (Gilles de Van) and musical dramaturgy (Dahlhaus, Bianconi, Feldman, Heller), however, highlight the importance of the constellation of characters and the complementarity of actions in the construction of the drama. Adopting the latter perspective, this article explores the distinctive characteristics of the twenty-six dramas written by Metastasio, considering the singular constellations found in each of them (in terms of status, kinship and emotions) as well as the convenienze teatrali imposed by the business of opera. We show how Metastasio built a twofold dramaturgy in his dramas to meet both the expectations of dramatic literature and the requirements of musical expression of emotions. This explains why the primo uomo (Poro) could be the antagonist of the hero (Alessandro) in Metastasio's Alessandro nell'Indie.
