El Escorial, Derand and Guarini: About Formal Control of Ribbed Spherical and Elliptical Vaults

Guarino Guarini’s ribbed vaults have been connected with Islamic sources. However, this connection relies almost exclusively on plans and visual observations from the church floor. By contrast, the vertical layout, although clearly shown in Guarini’s Dissegni di architettura civile ed ecclesiastica, and the intrados surface of the ribs have not been taken into account, except by Marco Boetti (Guarino Guarini, Umberto Allemandi, Torino, 2006). In this contribution, I will deal with some possible sources of Guarini’s designs for the ribbed vaults of Sainte-Anne-la-Royale in Paris, Padri Somaschi in Messina, San Lorenzo in Turin and San Gaetano in Nice. I will take into account not only the plan layout of the ribs, but also their shape in space, and the nature of the intrados surface, analysing such possible sources as the stereotomic treatise of François Derand and several Spanish stonecutting manuscripts connected with El Escorial.