A century before the Conquest of England, groups of pilgrim-warriors began to leave their native Normandy for southern Italy. Landless younger sons left in order to make their fortune elsewhere, as their Viking ancestors had done throughout Europe and beyond. Hired originally as mercenary soldiers by the Lombards, the Normans eventually became powerful lords in their own right. In the second half of the 11th century one of history's most reputed warriors, Robert Guiscard, achieved great fame and brought about Norman dominance in southern Italy; even conquering William himself looked to Guiscard for inspiration. Though the Normans were not particularly liked by any of the other nations on the peninsula, attempts to team up against them never succeeded, thanks in no small part to Guiscard's flamboyant leadership and style. An early enemy was the Pope, but he eventually became a friend, particularly after the Normans saved his state from the Holy Roman Emperor. Upon hearing of Guiscard's success many more Normans arrived to fight in southern Italy, all with the hope that they would earn land for their service. Guiscard's younger brother Roger was among those to arrive, soon (without much help from Guiscard) carving out a realm of his own and assisting in the subjugation of Puglia and Calabria. Guiscard and Roger schemed to add Sicily to their possessions, which was then in the hands of Arabs. They received papal blessing for their crusade, and in 1060 succeeded in capturing Messina after heavy fighting. While the rest of Sicily was taken over in coming years, Guiscard's ambition could not be contained in Italy. He dreamed of toppling the Byzantine Empire and crowning himself sublime in Constantinople. But it was not to be: after winning a few battles, great 70-year-old Guiscard succumbed to sickness on campaign and soon passed away (the Greeks, among others, breathed a sigh of relief). His Italian realm passed to Roger, who had by then solidified his hold on Sicily and rest of southern Italy.

Count Roger I, together with his son King Roger II (ruled 1101-1154) initiated a Golden Age in Sicilian history, a cultural renaissance that the troubled isle has seen precious little of since. The intellectual and artistic flowering took place because the rulers upheld religious and cultural tolerance, concepts as foreign to medieval Europe as are to most of the world today. If in battle the Normans were fierce, ingenious, and brutal, in peace they did not wish to destroy the existing fabric of life on the island. Arabs were allowed to continue practicing Islam, Christians, Jews, Greeks and Normans all attempted to live together. The two Rogers embraced the diversity they had found on the island, as did the two Williams who followed them (1154-1189), welcoming Western, Arab and Greek scientists, historians and artists to their court. One of the greatest geographers and cartographers of the Middle Ages, Al-Idrisi, took residence at the court of Roger II. The Norman king commissioned him to make an up-to-date map of the world, which he completed as a 400 kg silver sphere globe. Al-Idrisi also wrote a detailed geographical encyclopedia; many centuries later, Christopher Columbus used a map originally taken from his work. The Norman rulers maintained an elite Arab guard, and they particularly enjoyed keeping a harem, a legacy from the emirs they had booted off the island.

The Normans fortified Sicily with strategically placed castles, and proved very effective rulers, developing an efficient feudal state here as they had done in Normandy (and would do in England). As devout Christians the Normans built many churches; by the reign of Roger II, Arab and Greek artisans were employed in the construction not only of churches but also secular buildings. The resulting styles in art and architecture wonderfully reflect this mix: Greek and Arab artists worked side by side to produce the greatest Norman monuments, which include the Duomos of Cefalù and Palermo, Palermo's Norman Palace, and the magnificent Abbey of Monreale.