County of Sicily with Robert Guiscard. In fact, the seat of Roger I's government was the Calabrian town of Mileto. According to the historians Agostino Inveges and Matteo Camera Roger I started to use the title ""Great Count of Sicily and Calabria"" since 1096. After the death of Roger I the major change was the transfer of the capital: Palermo became the capital in 1112, when Roger II was invested with the County, after the regency of the mother Adelaide del Vasto. With this change, Sicily come to be governed by the central government, while the Calabrian territories became a provincial administrative unit.
Emirate of Sicily of the multi-ethnic County and subsequent Kingdom of Sicily, until those who had not already converted were expelled in the 1240s. Until the late 12th century, and probably as late as the 1220s, Muslims formed a substantial portion of the island's population. Their influence remains in some elements of the Sicilian language, as well as surnames and locations. In 535, Emperor Justinian I returned Sicily to the Roman Empire, now ruled from Constantinople exclusively. As the power of what is now known as the Byzantine Empire waned in the West, Sicily was conquered by the Rashidun Caliphate during the reign