The interior of one of the oldest churches in the city, formerly Gothic, was entirely remodelled in the churrigueresque style. Admire an exceptional set of frescoes (2,000m²), carried out in the early 18C, whose trompe l'oeil effects make the most of the Gothic vaults, particularly since a masterful restoration. Look out for the 16C altarpiece by Juan de Juanes in the chapel to the left of the entrance and the Calvary by Osona the Elder.