The peril that menaced European civilization in 1571 was that at last the Moslem powers of the Mediterranean were actually combining their sea forces for a great effort of maritime conquest. Their operations were still delayed by their traditional disposition to indulge in plundering raids, or to wait for the fall of a blockaded fortress, instead of making the destruction of the opposing sea power their first object. If the pashas of Selim's fleets had really understood their business, they might have destroyed the Christian squadrons in detail before they could effect their concentration in the waters of Messina. But the Turkish admirals let the opportunity escape them during the long months when the "Holy League" was being formed and its fleets made ready for action. That the danger was met by the organization of a united effort to break the Moslem power on the sea was entirely due to the clear-sighted initiative and the persistent energy of the aged Pius V. He had fully realized that the naval campaign of 1570 had been paralysed by the Christian fleet being directed, not by one vigorous will, but by the cautious decisions of a permanent council of war. He insisted on the armament of 1571 being under the direction of one chief, and exercising his right as chief of the League, Pius V had to select the commander of its forces; he named as captain-general of the Christian armada Don Juan of Austria. Don Juan was then a young soldier, twenty-four years of age. He was the son of the Emperor Charles V and his mistress, Barbara Blomberg of Ratisbon. His boyhood had been passed, unknown and unacknowledged by his father, in a peasant household in Castille. As a youth he had been adopted by a noble family of Valladolid. Then Philip II had acknowledged him as his half-brother, and given him the rank of a Spanish Prince. He studied at Alcala, having for his friends and companions Alexander Farnese, the "Great Captain" of future years, and the unfortunate Don Carlos. Don Juan's rank gave him early the opportunity of displaying in high command his marked genius for war. He was employed in expeditions in the Mediterranean, and directed the suppression of the Moorish revolt in Granada in 1570. He was then named "Capitan-General del Mar"--High Admiral of the Spanish fleets. Young as he was when Pius V appointed him commander-in-chief of the forces of the Holy League, his services by land and sea, as well as his princely rank, gave him the necessary prestige to enable him to command even older generals like Marco Antonio Colonna, the leader of the papal and Italian forces, and the veteran Sebastian Veniero, who directed those of Venice.