The term "Moors" refers primarily to the Muslim inhabitants of the Maghreb, the Iberian Peninsula, Sicily, and Malta during the Middle Ages. The Moors initially were the Berber autochthones of the Maghreb. The name was later also applied to Arabs. Moors are not a distinct or self-defined people, and the 1911 Encyclopaedia Britannica observed that "The term 'Moors' has no real ethnological value."

The first Muslim conquest of Sicily began in 827, though it was not until 902 that almost the entire island was in the control of the Aghlabids, with the exception of some minor strongholds in the rugged interior. During that period some parts of southern Italy fell under Muslim control, most notably the port city of Bari, which formed the Emirate of Bari from 847-871. In 909 the Aghlabid dynasty was replaced by Shiite Fatimids. Four years later, the Fatimid governor was ousted from Palermo when the island declared its independence under Emir Ahmed ibn-Kohrob. The language spoken in Sicily under Muslim rule was Siculo-Arabic.  In 1038, a Byzantine army under George Maniaces crossed the strait of Messina. This army included a corps of Normans that saved the situation in the first clash against the Muslims from Messina. After another decisive victory in the summer of 1040, Maniaces halted his march to lay siege to Syracuse. Despite his success, Maniaces was removed from his position, and the subsequent Muslim counter-offensive reconquered all the cities captured by the Byzantines.  The Norman Robert Guiscard, son of Tancred, invaded Sicily in 1060. The island was split between three Arab emirs, and the Christian population in many parts of the island rose up against the ruling Muslims. One year later, Messina fell, and in 1072 Palermo was taken by the Normans. The loss of the cities, each with a splendid harbor, dealt a severe blow to Muslim power on the island. Eventually all of Sicily was taken. In 1091, Noto in the southern tip of Sicily and the island of Malta, the last Arab strongholds, fell to the Christians. Islamic authors noted the tolerance of the Norman kings of Sicily. Ibn al-Athir wrote: "They [the Muslims] were treated kindly, and they were protected, even against the Franks. Because of that, they had great love for King Roger."  The Muslim problem characterized Hohenstaufen rule in Sicily under Holy Roman Emperors Henry VI and his son Frederick II. Many repressive measures were introduced by Frederick II to please the popes, who were intolerant of Islam in the heart of Christendom. This resulted in a rebellion by Sicilian Muslims, which in turn triggered organized resistance and systematic reprisals and marked the final chapter of Islam in Sicily. The complete eviction of Muslims and the annihilation of Islam in Sicily was completed by the late 1240s when the final deportations to Lucera took place.Answer this question using a quote from the following article:

what role did it play?
This army included a corps of Normans that saved the situation in the first clash against the Muslims from Messina.