The Chapel of the Holy Trinity at the Zisa is a Norman building that functioned as a palatine chapel since it is located just north of the palace. There was probably an earlier nucleus of Byzantine and then Arab ancestry. It was William I, known as William the Bad, and later his son and successor William II, who made it a private chapel for the sovereign. With a single nave and facing east, the chapel is surmounted by a small dome resting on an octagonal drum. Originally, it is thought that there was a direct, covered connection through which rulers could easily reach the chapel from the palace and attend church services.
