ABSTRACT
Saint-Paul-Saint-Louis (1627–40) was the first church in Paris with a large-sized crossing dome (a span of approximately 12 m). The structural behaviour of this “vault”, when checked with a calculation program, reveals certain similarities to a masonry dome, although it was realized in timber like the outer structure. This tour-lanterne may be compared with the smaller one on the Église des Carmes in Paris. Both are probably based on illustrations from the treatise Le théâtre de l’art de Charpentier by Mathurin Jousse, who was connected with the architects of Saint-Paul-Saint-Louis. Saint-Paul-Saint-Louis turned out to be highly influential. Although its dome is structurally speaking neither logical nor efficient, it constituted one of the first steps in a process which eventually led to great domes such as the Dôme des Invalides. Similar experiments at the Leuven Jesuit church (1650–57), inspired by the Parisian example and its aftermath, were unfortunately never realized.
