The Byzantines had possession of Sicily off and on for hundreds of years, until they finally lost it forever by 1040. Arabs and Moors held it for a few decades before Norman mercenaries wandered down into Italy and decided to stay.
Those Norman mercenaries included the infamous (for the Byzantines) Robert Guiscard and several of his many (at least 11) brothers. The youngest brother to make it to southern Italy was Roger. Robert Guiscard was a soldier whose strength was in conquering, not ruling. He took Apulia and Bari from the Byzantines and earned the title of Duke of Apulia. Later he made an impressive effort to become the emperor in Constantinople. Generously, he gave the territory he had won in Sicily to brother Roger. In time, Roger pushed the Moslem emirs off the rest of the island and became Count of Sicily.
The art in Sicily during the time of Roger I and his descendants/successors demonstrated their deep admiration of the Eastern Roman Empire. The mosaics at Monreale, the Palatine Chapel and Cefalu all bear the unmistakable mark of Byzantine culture. They include looming Christ Pantocrators in the church apses, Mary seen always with Jesus, and the porphyry sarcophagus of a Sicilian king .
Even more interesting is how the mosaics depicted Norman Sicilian kings. Above you can see an image of the Byzantine Emperor Constantine Monomachos wearing the typical 11th century attire for an emperor. It includes a distinctive sash and belt (lorum), and the red shoes worn by emperors. Below are images of an angel and the Norman Sicilian rulers as depicted in the mosaics of their churches in similar clothing.
The Attire of Byzantine Rulers
William II at Monreale:
Even some of the angels at Monreale were attired as Byzantines:
And another image of William II, at the dedication of Monreale.
These mosaics make evident that the rulers of this great medieval island kingdom admired Byzantine culture. They used its symbols of wealth and power to demonstrate their own strength. Unfortunately, the Norman rulers only lasted a few years after the death of William II (the Good). It ended with the overthrow and murder of young William III by the Holy Roman Emperor Henry VI in 1194. Many of Sicily’s later rulers never spent much time there, and by then the Latins had occupied Constantinople.
The Byzantine/Eastern Roman Empire had passed its peak by the late 12th century when William II built Monreale. Even so, these magnificent mosaics represented their view of the highest level of culture and sophistication in Europe and the one its rulers found most worthy of imitation.