 Charles III of Spain enlarged the chapel, incorporating a large square cupola with a gable roof.The church consists of a central circular structure with a grand north-facing portico entrance facade of five white limestone arches decorated with Tuscan pilasters.A gallery of a further five arches on either side of this join the central church portico with the complementary style of the smaller red-brick arched walkways of the Casa de Infantes to the east and Casa de los Cabeleros (knights) to the west enclosing the renamed Plaza de San Antonio on three sides.