A cathedral with the appearance of a military fortress.

The cathedral is Romanesque in origin, with subsequently added Gothic elements and Renaissance ornamentation.

Construction began in the 12th century, on the orders of Bishop Bernardo de Agén; however, work continued until the 16th century. The church has three naves, a main chapel with an ambulatory and a dome. Its chapels include particularly San Pedro with a wrought iron grille by Juan Francés, the Anunciación, with Mudejar details, and the San Marcos chapel. Los Arces chapel contains the mortuary statue of Martín Vázquez el Doncel, an exceptional work dating from the late 15th century. In the south-facing wall of the presbytery you will find the Gothic-style tomb of Bishop Alonso Carrillo de Albornoz, Cardinal of San Eustaquio, as well as that of the knight Gómez Carrillo de Acuña and his wife.