The Cefalù Cathedral mosaic decoration extends over the surface of the apse, the cross vault and the walls below. The mosaics were probably made in three different phases: they began in 1148 with the apse and the cross vault, and then in the following years they moved on to the walls.
The Byzantine style, shown in particular by the richness of the details, the sumptuousness of the clothing and a marked two-dimensionality, suggest the presence of workers coming directly from Constantinople. This mixture of styles, primarily Byzantine and Nordic Romanesque, makes Cefalù unique in its kind, as well as making it an international factory in which artists of different cultures and styles worked.
The mosaics are divided into four bands, each delimited by frames, geometric and plant decorations. The centrepiece of the mosaic complex, which covers about 650 square metres, is undoubtedly the Christ Pantocrator, who stands out regally in the apsidal dome; in the register below, the Virgin Mary, standing and praying, is placed in the centre, with two pairs of archangels at the sides, dressed in sumptuous and elegant Byzantine clothing. Raphael, Michael, Gabriel and Uriel are the archangels present in the mosaic.
St. Peter, St. Paul and the apostles Philip, James, Andrew, Simon, Bartholomew and Thomas and the four evangelists Mark, Matthew, Luke and John are depicted in the two lower registers, arranged in groups of three.
On the walls of the Bema, the Holy Kings, the Holy Deacons, the Holy Warriors, the Fathers of the Western and Eastern Church, the Prophets and the Holy Theologians are portrayed, arranged on four registers.
In particular, Melchizedek (within a lunette), Hosea, Moses are depicted on the left-hand wall; Joel, Amos and Obadiah are depicted in the lower register; and the deacons Peter, Vincent, Lawrence and Stephen are also depicted. Further down, Saints Gregory, Augustine, Sylvester and Dionysius are represented.
Abraham (within a lunette), David and Solomon are depicted on the left-hand side; the prophets Jonah, Micah and Naum are depicted in the lower register; and the warrior saints Theodore, George, Demetrius and Nestor are also depicted. The eastern saints Nicholas, Basil, John Chrysostom and Gregory Nazianzen can be seen lower down.
In the cross’s four wings, the divine sky opens up with the Cherubim and Seraphim. All the figures in the Cefalù mosaic cycle are majestic and hieratic, isolated in space by the precious gold background, typical of Byzantine art, and accompanied by inscriptions in Greek and Latin indicating their names.