The church is called this because it was built on the foundation of a palace donated by Alfonso VII of Castile.It is also known as “La Aguja” or “La Imperial”. The church was founded in the 11th century, but reconstructed in the 12th and extended in the 16th. The church has three naves finishing in abbatial chapels.Over the transept the octagonal cupola rises, that on the outside extends to the pyramidal Gothic style tower.There is noteworthy high reredos inside work by Arnao of Brussels.