In the Greek islands the activity of the Turkish fleet produced positive and permanent results; Lesbos was taken in 1462, and to the list of Turkish successes in these years were soon added Lemnos, Imbros, Samothrace. Much more valiant defenders of their island were the Knights of Rhodes, whom the Sultan was especially desirous of punishing for the part they had taken in the already mentioned Venetian expedition against Asia Minor. In 1480 a large Ottoman fleet of about one hundred ships appeared in sight of the island, and a bombardment was begun, but the fortifications proved too strong for the Turkish guns to make any impression, though the siege lasted from early in May till the end of August, in which time, despite the assaults made on the citadel, only one tower was taken. The Grand Master, Pierre d’Aubusson, and his brother, had prepared most intelligently for the crisis by collecting from all provinces of the Order money, which they used in providing weapons, especially cannon. They had been furnished also by the Pope, just before the siege began, with a large store of food and provisions. Finally, after a heroic defense of eighty-nine days, two Neapolitan ships forced their way into the harbor and broke up the blockade. In the Wallachian lands the Ottomans met a redoubtable warrior, who, in the annals of the Roumanian people, takes such a high place as a champion against the Turks that the record of his deeds gives him a rank alongside Hunyadi and Scanderbeg. Vlad, the Prince of Wallachia, 1456-1462, called by the Hungarians the Devil, and with equal significance spoken of by the Turks as the Impaler, had a reputation for violence even among his own people. He repressed the internal troubles of his vassals with an iron hand; for after Mircea’s death the country had gone through the same period of divisions and intrigues that is found with such frequency in all the Balkan lands, making them, as we have seen, an easy prey for the Ottoman. It is told how Vlad brought Wallachia to a peaceful state by the execution of 20,000 men, and how, afterwards, in the same drastic style, he resolved to put an end to the annual tribute of 500 children demanded by his overlord the Sultan. Looking for allies in carrying on the resistance to Mohammed, he helped Stephen IV to secure the throne of Moldavia, and married a relative of Matthias, King of Hungary. Mohammed resolved to nip in the bud the independent movements of his dangerous vassal, and sent a renegade Greek official, Catabolinus, with a corps of 2000 Turks to depose Vlad and to replace him by his brother, Radu. Vlad, having surprised this small force, impaled all the prisoners he took; to the pasha who led them was accorded the honor of being impaled on the longest stake. After this outrage the Sultan sent three ambassadors to reinforce his demands; but, when the Moslem delegates refused to remove their turbans in his presence, Vlad ordered their headgear to be nailed to their heads.