Of the maritime expeditions of the Northmen we have already spoken. For many centuries they were the terror of Europe, North and South. The sea-kings of Norway appeared before Constantinople in 866, and afterward a body-guard of the emperors of the East was composed of these pirates, who were called the Varangians. Even before the death of Charlemagne their depredations brought tears to his eyes; and after his death they pillaged and burnt the principal cities of France, and even his own palace at Aix-la-Chapelle. They carried their arms into Spain, Italy, and Greece. In 844 a band of these sea-rovers sailed up the Guadalquiver and attacked Seville, then in possession of the Moors, and took it, and afterward fought a battle with the troops of Abderahman II. The followers of Mohammed and the worshippers of Odin, the turbaned Moors and the fair-haired Norwegians, here met, each far from his original home, each having pursued a line of conquest, which thus came in contact at their furthest extremes.
The Northmen in Italy sold their swords to different princes, and under Count Rainalf built the city of Aversa in 1029[332]. In Sicily the Northern knights defeated the Saracens, and enabled the Greek Emperor to reconquer the island. Afterward they established themselves in Southern Italy, and took possession of Apulia. A league formed against them by the Greek and German Emperors and the Pope ended in the utter defeat of the Papal and German army by three thousand Normans, and they afterward received and held Apulia as a Papal fief. In 1060 Robert Guiscard became Duke of Apulia and Calabria, and at last of the whole kingdom of Naples. Sicily was conquered by his brother, Count Roger, who, with a few Northmen, routed vast numbers of the Saracens and completed the subjection of the island, after thirty years of war. Meantime his brother Robert crossed the Adriatic and besieged and took Durazzo, after a fierce battle, in which the Scandinavian soldiers of the Greek Emperor fought with the Normans descended from the same Scandinavian ancestors.