
The clash between Muslim, mainly Ottoman, power in the east, and Christian, mainly Spanish, power in the west developed along a double frontier. The rise of Muslim powers brought substantial aggregation and consolidation to Eastern Basin. Christians controlled most crucial islands and peninsulas till the Norman conquest of Sicily and the Crusades in the eleventh century.

The most influential twentieth-century historian of the early modern Mediterranean, Fernand Braudel, insisted that deep geographical structures and long-term economic conjunctures made for a fundamental unity of the region, transcending political and religious boundaries.
