Work on the Collegiate Church began in 1160 during the reign of Alfonso VII, however, the building would not be completed until the end of the 13th century. It has three naves and a transept crowned by a magnificent dome. Also worthy of note is the northern entrance, on one of the archivolts of which we find a representation of the Old Men of the Apocalypse. The Western Entrance, also referred to as the Royal Entrance has a richly decorated, polychrome Gothic portico, quite a unique feature. The combination of Romanesque and Gothic styles make the church especially attractive.