After both the Hungarian military commander John Hunyadi and the Serbian despot Đurađ Branković died in 1456, the Ottomans attacked Serbia again, capturing the fort in 1458 and the whole of Serbia in 1459, but they failed to take Belgrade, which was held by the Hungarians. Hadım Şehabeddin again expanded and strengthened it in preparation for the attack on Belgrade. With expansion of the walls and ramparts and the building of the dry moat, they effectively turned it into the starting point of the constant harassment of the Hungarian defenders of Belgrade. The Ottomans began calling the fort havala, which means obstacle, and that gave the name to the entire Avala mountain. One of the surviving Serbian sources say that "from the ruins of the medieval little town of Žrnov, which was named Avala, the Turks built a proper marauders' tower, roofed with lead. From there, they ruled the Belgrade surroundings, which became almost completely desolate". Using artillery, the Hungarians attempted to retake Žrnov in 1515 but were decisively defeated, losing all their heavy artillery. Another Serbian inscription from 6 May 1515 mentions the battle and the fort, now already called Avala: разби Балиль бегь Јаноша хердељскога војеводу подь Хаваломь ("Bali-beg defeated John of Erdely under [H]avala").