The interior is described by a testimony from 1696 which mentions a "vast, large, beautiful and dazzling choir, decorated with stucco and very clear thanks to the width of the windows"."il Choro vuoto, grande, bello e vistoso, adornato con stucchi et molto chiaro per la largezza delle finestre" Similarly, the chapels that have been preserved have been enlarged. Several accounts also describe the richness of the materials used: stucco, Carrara marble, black marble.
