On July 3, 2015, the UNESCO World Heritage Committee, meeting in Bonn, added the site to the World Heritage List with the following justification: “The group of buildings constituting the Arab-Norman route represents an exceptional universal value as an example of coexistence and interaction between different cultural components of heterogeneous historical and geographical origin (cultural syncretism). This phenomenon has generated an original architectural style, where Byzantine, Islamic, and Romanesque elements are masterfully fused, capable of creating unique combinations, of exceptional artistic value and extraordinary unity.”

The heart of the Arab-Norman route is the Royal Palace, a symbolic monument of the wealth, political power, and culture of the Norman kingdom. Inside, housed like a treasure, is the Palatine Chapel: “the most beautiful that exists in the world, the most stunning religious jewel imagined by human thought and executed by the hands of an artist” (Guy de Maupassant).