Legend has it that William II had the idea of this cathedral in a dream when, during a hunting expedition, he fell asleep under a carob tree. While slumbering, the Virgin Mary appeared to him, indicating where a treasure chest was located -- and with this loot he was to build a church in her honor. Legends aside, the real motives that led William to build a new church were dictated by supremacy: The struggle between temporal and secular power was ever-present. It is the last -- and the greatest -- of the series of Arabo-Norman cathedrals with Byzantine interiors.
For the most part, the exterior of the building is nothing remarkable: The facade, facing west in Piazza Guglielmo, is flanked by two towers, one of which was never completed. The addition of a portico in the 18th century covered the fine bronze doors created by Bonanno of Pisa in 1186, who also created the Bell Tower atop the Leaning Tower of Pisa. The northern portico, which is the main entrance to the cathedral, has a doorway created by Barisano da Trani (1179). The portico also has two bronze statues from the 1970s; on the left is the Virgin Mary, while on the right is William II offering a model of his cathedral to her. The real highlight of the exterior are the exquisite apses, seen from Via dell'Arcivescovado (go under the small archway just after the north portico) with their interlacing of limestone and lava to create intricate geometric shapes.
The interior of this rather unadorned rough-looking church, measures 102m x 40m (335 ft. x 131 ft.) and presents a floor plan that combines elements of both a Latin and Byzantine basilica, which was typical of Norman architecture. It has a wide central nave and two smaller aisles, each flanked by nine columns on either side topped with different capitals with religious symbols and figures. Of all the eighteen columns, only one is not made of granite: The first on the right side is made of cipollino marble, frailer than granite, representing the archbishop. The roof made of wood and showing a stark Saracen influence, is an 1811 replica of the original, which was destroyed in a fire.
Needless to say, the mosaics are the principal attraction of the cathedral, covering some 6,400 sq m (68,889 sq ft.) of the interior and utilizing some 2,200 kg (4,850 lb.) of gold. The mosaics cover the entire surface of the cathedral except for the ground level, which is decked out in marble. There are in total about 130 individual mosaics, depicting biblical and religious events. Episodes from the Old Testament are depicted in the central nave (the ones representing the life and times of Noah are particularly noteworthy), while the side aisles illustrate scenes from the New Testament. The dominating mosaic is the Christ Pantocrator on the central apse of the main altar, similar to the ones in the Palatine chapel and in the cathedral in Cefalù. Right below it is the mosaic of the Teokotos (Mother of God) with the Christ child on her lap. The small window above the main entrance always casts a light on this mosaic. Teokotos is flanked by angels and saints, the most remarkable being the one of Thomas à Becket, the Archbishop of Canterbury who was murdered on the orders of William's father-in-law, Henry II. It is one of the earliest portraits of the saint. (He is the second from the right.)
Two other mosaics worth mentioning are on other side of the presbytery, over the royal and episcopal thrones: The one over the former shows William II being crowned by Christ, while the latter depicts William offering a model of the cathedral to the Virgin Mary. The north transept leads to the heart of St. Louis, who was buried here after a funeral cortege stopped in Monreale on the way back from Tunisia; it also houses the Treasury. In the south transept lies the pantheon of the cathedral -- William I, William II, and Margaret of Navarre. William I's tomb is preserved intact in its royal porphyry casing, while his son's, presumably destroyed in a fire, was made from scratch in typical 16th-century funeral style, with his life and accomplishments etched on the sarcophagus. From the rooftop entrance to the right of the main door, after a very steep -- and sometimes perilous -- climb, you're offered the most wonderful panorama over the golden valley, eastern Sicily and, on a clear day, the Aeolian Islands.
The fine cloisters is the only remaining original part of the abbey. It is perfectly square and lined with groups of twin columns on each side, four at every corner, for a total of 228 columns; each group supports a capital (no two are alike) adorned with scenes from Sicily's Norman history. The knights depicted resemble those in the Bayeux Tapestry, which chronicles the Battle of Hastings and strongly reflects the style of 12th-century Provence. Also among the designs are animals, monsters, Christian symbolism, and even the sacrifice of a bull. In the cloisters the monks grew the trees of paradise -- palms, olives, figs, and pomegranates. In the southwest corner is an exquisite enclosure that outlines a splendid fountain in the shape of a palm tree.