The Epistle wall chapel houses a small early seventeenth century altarpiece by local painters Juan de Frías Salazar and Francisco de Adán, presided over by a Romanesque carving of St. Gregory the Great.
The nearby arcosolium houses the image of Queen Blanche of Navarre, from the cloister.
For an explanation of the main altarpiece, go to the presbytery and press 6.