The start of the Delhi Sultanate in 1206 under Qutb al-Din Aibak introduced a large Islamic state to India, using Central Asian styles. The important Qutb Complex in Delhi was begun under Muhammad of Ghor, by 1199, and continued under Qutb al-Din Aibak and later sultans. The Quwwat-ul-Islam Mosque, now a ruin, was the first structure. Like other early Islamic buildings it re-used elements such as columns from destroyed Hindu and Jain temples, including one on the same site whose platform was reused. The style was Iranian, but the arches were still corbelled in the traditional Indian way.