The oldest church in the city, believed to have been built in the 10th century by Ramiro II, “The Great”, the main objective being to build a convent where his daughter Elvira could live and pray. The old church had a Greek cross floor plan, of which a transept with semi-circular arches and an umbrella vault. It was abandoned in the Middle Ages and has continued to be a place of prayer up to the present day, as part of the parish of San Martin.
According to some researchers, the monastery contained the old royal pantheon of Leon. The original building was designed in the Visigothic-Mozarabic style. Only a small chapel remains, built in the 16th century, along with remnants of mural paintings.