Mudejar architecture

This is the church of Santiago de Arrabal (Saint James on the outskirts). It is a thirteenth century Romanesque and Mudejar construction. I am in the middle of trying to figure out the best way to understand the almost obsessive use of Islamic features in Christian architecture. Of note here is the detached bell tower, which is modelled after the detached minarets of mosques. The tower is well older than the church, and may belong to an older mosque on the sight. At any rate, it is spectacular.