Masjid. Both capitals of the Bengal Sultanate, first Pandua or Adina, then from 1450 Gauda or Gaur, started to be abandoned soon after the conquest of the sultanate by the Mughals in 1576, leaving many grand buildings, mostly religious. The materials from secular buildings were recycled by builders in later periods. While minarets are conspicuously absent in most mosques, the Firoz Minar was built in Gauda to commemorate Bengali military victories. The ruined Adina Mosque (1374–75) is very large, which is unusual in Bengal, with a barrel vaulted central hall flanked by hypostyle areas. It is said to be the largest mosque in the sub-continent, and modeled after the Ayvan-e Kasra of Ctesiphon, Iraq, as well as the Umayyad Mosque of Damascus. The heavy rainfall in Bengal necessitated large roofed spaces, and the nine-domed mosque, which allowed a large area to be covered, was more popular there than anywhere else. After the Islamic consolidation of Bengal was complete, some local features continued, especially in smaller buildings, but the Mughals used their usual style in imperial commissions. Indo-Islamic architecture of Gujarat The distinctive Indo-Islamic architecture style of Gujarat drew micro-architectural elements from earlier Maru-Gurjara architecture and employed them in mihrab, roofs, doors, minarets and facades. In the 15th century, the Indo-Islamic style of Gujarat is especially notable for its inventive and elegant use of minarets. They are often in pairs flanking the main entrance, mostly rather thin and with elaborate carving at least at the lower levels. Some designs push out balconies at intervals up the shaft; the most extreme version of this was in the lost upper parts of the so-called "shaking minarets" at the Jama Mosque, Ahmedabad, which fell down in an earthquake in 1819. This carving draws on the traditional skills of local stone-carvers, previously exercised on Hindu temples in the Māru-Gurjara and other local styles. Under the Gujarat Sultanate, independent between 1407 and 1543, Gujarat was a prosperous regional sultanate under the rule of the Muzaffarid dynasty, who built lavishly, particularly in the capital, Ahmedabad. The sultanate commissioned mosques such as the Jami Masjid of Ahmedabad, Jama Masjid at Champaner, Jami Masjid at Khambhat, Qutbuddin Mosque, Rani Rupamati Mosque, Sarkhej Roza, Sidi Bashir Mosque, Kevada Mosque, Sidi Sayyed Mosque, Nagina Mosque and Pattharwali Masjid, as well as structures such as Teen Darwaza, Bhadra Fort and the Dada Harir Stepwell in Ahmedabad. The Champaner-Pavagadh Archaeological Park, the 16th