Hunyadi led the Hungarians in this his last campaign. The lower town was taken by the Turks after great loss of life; but the upper town made a protracted resistance. The Christian knights in a notable sortie attacked the batteries of the enemy, captured all the guns, and wounded the Sultan himself. Mahomet was compelled to raise the siege after losing fifty thousand men. It was the last feat of the Hungarian patriot. He died twenty days after this signal success. It was fifty years before Belgrade was again attacked and captured and the road was opened for the invasion of Hungary and Vienna. In all these campaigns Mahomet personally led his armies in the field, with the exception of those for the invasion of the Crimea, the attack on Rhodes, and the capture of Otranto, where he delegated the task to able generals, of whom he appears to have had an abundant supply. But there never was a great commander who more completely dominated the generals under him and maintained his supremacy in the State. He made no confidences as to his intended military operations, or what were his immediate objects of attack. There were no councils of war. His armies were collected, year after year, on one side or other of the Bosphorus, without any one knowing their destination. When, on one occasion, one of his generals asked him what was his next object, he replied that if a single hair of his beard knew what his intentions were he would pluck it out and cast it into the fire. He held secrecy and rapidity to be the first elements of success in war, and he acted on this principle. With the exception of the single case of the invasion of Wallachia, the provocation for war was in every case on the part of the Sultan. Invasion and attack were preceded by laconic messages calling upon the State or city aimed at to surrender, and the actual attack was made with the shortest possible delay. Having determined on war and invasion, his object was pursued with the utmost vigour, and wholly regardless of the loss of life. As a rule, his campaigns were short; but the war with Venice was an exception. It lasted for many years. It consisted mainly of attacks on strongholds of the Republic in the islands of the Archipelago and the coasts of Greece and Albania, where the fleets of the two Powers played a large part. The conquest of Albania also was only effected after a struggle spread over many years, in which the patriot hero, Scanderbeg, defeated successive attacks by Ottoman armies enormously exceeding his native levies. It was not till after the death of this great chief, in 1467, that Mahomet was able to wear down opposition in Albania by sheer force of numbers.