The cathedral was built between the 12th and 13th centuries. It has three doors; the north door is dedicated to Santa María, to the south is the Portal or Peones door, and the main doorway is the Final Judgement in the proto-Gothic style, which depicts the fulfilment of a sentence decreed by the Eternal Judge.
The cathedral has a floor plan in the shape of a Latin cross with three naves, and of particular note is the transept, which is completely Gothic. It has ogive vaulted ceilings, except for the chapels in the apse which are covered with semi-circular and pointed barrel vaults. One of the highlights on the interior is the altarpiece pained by Pedro Díaz de Oviedo. Another outstanding feature is the stone image of the White Virgin, dating from the 12th century. The cathedral is crowned with a Romanesque tower at one side of the Judgement doorway, and a Renaissance brick tower on the other side.