Final answer:
The mosaic panel depicting William II standing next to the Enthroned Christ in the cathedral of Monreale commemorates Divine approval of rulership.
Step-by-step explanation:
In the cathedral of Monreale, the mosaic panel depicting William II standing next to the Enthroned Christ, with Christ placing his hand on William's crown, is believed to commemorate Divine approval of rulership. This panel depicts the notion that William II's rule as king is divinely sanctioned and endorsed by the Enthroned Christ, emphasizing the religious legitimacy of his reign.