On the eve of the Norman conquest of southern Italy and Sicily, the central Mediterranean resided in the sphere of Islam. Aggressive elements of its faithful dominated the north and south shores and the islands in-between at the very middle of the sea. Muslim pirates plagued both the Strait of Messina and the Sicilian Channel. Constantinople, remnant of the Eastern Roman Empire, fought fitfully to hold on to what little it still possessed on the lower Italian Peninsula. Meanwhile, the papacy was powerless to assert itself over the region, and the so-called Holy Roman Empire under the German kings only sporadically intervened in the chaotic affairs that prevailed south of Rome. The ‘middle sea’ was effectively divided in half, and east–west commerce was limited to Muslim and Jewish merchants along with a handful of their Western trading partners such as the Amalfitans. All dynamism on the sea seemed to emanate from the East. The rise of Norman sea power in the central Mediterranean under the inexorable Hautevilles irrevocably transformed the geopolitical and economic impetus on the sea and gave it a decided tilt to the West. The Mediterranean world would never be the same again. It was, quite literally, a sea change.

At the height of the Kingdom of Sicily under Roger II, the Normans held sway over both the north and south littorals of the central Mediterranean and the intervening islands. They had supplanted the ‘Saracens’ and swept their pirates from the sea, replacing them with Sicilian ships under the command of a gifted amiratus, George of Antioch. As a result, the ‘middle’ sea was opened to Christian as well as Muslim commerce – for a price.