San Nicolò Regale is one of the best-preserved examples of the Arab-Norman architectural style that flourished in Sicily under the Norman kings of the 12th century. The church is a cube topped by three domes, with blind arches and carved stone panels on the facade that look as much Arab as Christian. It was built by Roger II around 1124 and is one of the finest small Norman churches on the island.
The interior is simple — three small naves with no elaborate decoration — which makes the exterior all the more memorable by contrast. The church is a UNESCO World Heritage Site as part of the Arab-Norman Palermo and the Cathedral Churches of Cefalù and Monreale complex.