The beginning of the century had seen the growth of the Corsairs’ strength to a most alarming extent.  While all the European Powers were fighting among themselves, these Barbary Corsairs (as they were later called) had become the terror of the Western Mediterranean.  Spain, by its unrelenting persecution of the Moriscoes, following on centuries of bitter conflict between Christian and Mussulman, had earned the undying hatred of the dwellers on the North African coast, many of whom were the children of the expelled Moors.  These Moors had wasted their energy in desultory warfare up to the beginning of the sixteenth century, when the genius of the two brothers, Uruj and Khair-ed-Din Barbarossa, had organised them into the pirate State of Algiers, which was to be a thorn in the side of Christendom for over three centuries.  The Corsairs were not content with merely attacking ships at sea:  they made raids on the Spanish, Italian, and Sicilian sea-boards, burning and looting for many miles inland.  The inhabitants of these parts were driven off as captives to fill the bagnios of Algiers, Tunis, Bizerta, and other North African towns.  These prisoners were used as galley slaves, and the life of a galley slave was generally so short that there was no difficulty of disposing of all the captives that could be seized.  Cupidity, allied with fanaticism, gave this state of war a cruelty beyond conception:  both sides displayed such undaunted courage and such fierce personal hatred as to make men wonder, even in that hard and bitter century.  Those low-lying galleys, which were independent of the wind, were ideal pirates’ craft in the gentle Mediterranean summer, and many a slumbering Spanish or Italian village would be startled into terror by their sudden approach.  The audacity of their methods is illustrated by the raid on Fundi in 1534, when Barbarossa swooped down on that town simply to seize Giulia Gonzaga—­reputed the loveliest woman in Italy—­for the Sultan’s harem:  the fair Duchess of Trajetto hardly escaped in her nightdress.

The Eastern Mediterranean, after the capture of Rhodes, was almost entirely a Turkish preserve.  Though Venice at this period still kept her hold on Cyprus and Crete, the former of which was not yielded by the Republic till 1573 and the latter till 1669, yet the Treaty of Constantinople in 1479 had definitely reduced the position of Venice in the Levant from an independent Power to a tolerated ally.  The growth of the Ottoman sea power had been alarming enough, but it became a distinct menace to the Christian Powers of the Mediterranean when the Corsair chiefs of the North African coast became Turkish vassals.  All the African coast from Morocco to Suez, the coast of Asia Minor, and the European coast from the Bosphorus to Albania (with the exception of a few islands), were in Turkish hands.  From 1475, with the conquest of the Crimea, the Black Sea had become a Turkish lake, and under Solyman the Magnificent the Turks had become masters of Aden and the Red Sea, with a strong influence along the Arabian and Persian coasts.