The city was extremely heavily fortified, much of it remains till today. Two major attacks by Osmanic troops were fended off by a few thousands knights against over 50.000 enemies. Even catapulting thousands of huge stones and iron balls to destroy the multi-ring thick defense walls in 1140, 1440 and finally 1480 did not help. Indeed, in one of the battles over 10.000 attackers were killed with just about hundred defenders lost. In 1522, an entirely new sort of force arrived: 400 ships under the command of Sultan Suleiman the Magnificent delivered 100,000 men to the island. Against this force the Knights, under Grand Master Philippe Villiers de L'Isle-Adam, had about 7,000 men-at-arms and their fortifications. The siege lasted six months, at the end of which the surviving defeated Hospitallers were allowed to withdraw. Indeed they joined the defense of the island of Malta for an extended period.