The present Nebojša Tower was built c.1460 by the Hungarians, who ruled Belgrade at the time. When it was built, it was located at the entrance into the city's "Danube port", in the Lower Town of the fortress and was part of the defense system which was protecting Belgrade from the Ottoman invasion after the Siege of Belgrade in 1456. During the 1521 Siege of Belgrade, cannons from the tower successfully defended the city from July to August, until the Ottomans managed to set the tower on fire. Only then, they managed to conquer the city. One chronicler of the siege wrote: ""In the lower fortification of Belgrade on the Danube towards Mustafa–pasha position there was a tower. That tower was used as a stronghold by the faithless (Christians). It prevented assault. When assault was made yesterday many of them were killed by canons from the tower. After destruction that tower was put on fire today by a vanquisher. The faithless were beaten up and gave in. From the position of Mustafa-pasha an opportunity for assault was thus created."" The sultan Suleiman the Magnificent ordered for the tower to be rebuilt.