throughout Mughal rule. In 1685, Aurangzeb dispatched his son, Muhammad Azam Shah, with a force of nearly 50,000 men to capture Bijapur Fort and defeat Sikandar Adil Shah (the ruler of Bijapur) who refused to be a vassal. The Mughals could not make any advancements upon Bijapur Fort, mainly because of the superior usage of cannon batteries on both sides. Outraged by the stalemate Aurangzeb himself arrived on 4 September 1686 and commanded the siege of Bijapur; after eight days of fighting, the Mughals were victorious. Only one remaining ruler, Abul Hasan Qutb Shah (the Qutbshahi ruler of Golconda), refused to surrender. He and his servicemen fortified themselves at Golconda and fiercely protected the Kollur Mine, which was then probably the world's most productive diamond mine, and an important economic asset. In 1687, Aurangzeb led his grand Mughal army against the Deccan Qutbshahi fortress during the siege of Golconda. The Qutbshahis had constructed massive fortifications throughout successive generations on a granite hill over 400 ft high with an enormous eight-mile long wall enclosing the city. The main gates of Golconda had the ability to repulse any war elephant attack. Although the Qutbshahis maintained the impregnability of their walls, at night Aurangzeb and his infantry erected complex scaffolding that allowed them to scale the high walls. During the eight-month siege the Mughals faced many hardships including the death of their experienced commander Kilich Khan Bahadur. Eventually, Aurangzeb and his forces managed to penetrate the walls by capturing a gate, and their entry into the fort led Abul Hasan Qutb Shah to surrender peacefully. Military equipment Mughal cannon making skills advanced during the 17th century. One of the most impressive Mughal cannons is known as the Zafarbaksh, which is a very rare composite cannon, that required skills in both wrought-iron forge welding and bronze-casting technologies and the in-depth knowledge of the qualities of both metals. Aurangzeb military entourage consisted of 16 cannons including the Azdaha Paikar (which, was capable of firing a 33.5 kg ordnance) and Fateh Rahber (20 feet long with Persian and Arabic inscriptions). The Ibrahim Rauza was also a famed cannon, which was well known for its multi-barrels. François Bernier, the personal physician to Aurangzeb, observed versatile Mughal gun-carriages each drawn by two horses. Despite these innovations, most soldiers used bows and arrows, the quality of sword manufacture was so poor that they preferred to use ones imported from