The study is aimed at reconstructing the historical process at the base of any significant theatre architecture. The modern space for the show is no longer intended as a direct derivation from classical types, but as a product of the transformation of the urban fabric in our cities. The research was conducted at the academies, state and municipal historical archives of numerous towns, in particular Rome, Milan, Mantua, Ferrara, Venice, London and Prague. All images are original. The work also includes the list of about 700 major Italian historical theatres.