The Cathedral of San Pedro de Jaca, is one of the most characteristic and oldest of Romanesque art in Spain. The construction was started almost at the same time as the cathedral of Santiago de Compostela in the last quarter of the XIth century.

The temple consists of a main hall, flanked by two other minor ones, each of which connects with one of the apses. Each wall between the ships is made up of three cylindrical pillars that alternate with three other cruciform, holding each pair a half-point arc. The dome is held on a cruise through tubes or conical supports and arches of half a point of reinforcement. It is the oldest Romanesque dome of Spain.