Originally, the Latin term clipeus referred to the typical shield used by Greek soldiers, but during the Middle Ages and later in the Renaissance period, the term clipei was used to refer to the scenes inscribed inside a circle in a cycle of frescoes or mosaics. The clipei of the Monreale choir’s four ogival arches feature images of angels, kings and prophets. Arranged in a crescendo, they tell the story of salvation along with the rest of the mosaic cycle.