Q: Who was the first sultan of Delhi Sultanate?  

The Delhi Sultanate was a Muslim sultanate based mostly in Delhi that stretched over large parts of the Indian subcontinent for 320 years (1206-1526). Five dynasties ruled over the Delhi Sultanate sequentially: the Mamluk dynasty (1206-90), the Khilji dynasty (1290-1320), the Tughlaq dynasty (1320-1414), the Sayyid dynasty (1414-51), and the Lodi dynasty (1451-1526). Three dynasties (Mamluk, Khilji and Sayyid) were of Turkic origin, one dynasty (Tughlaq) was of Turko-Indian origin, and the last dynasty (Lodi) was of Pashtun origin. The sultanate is noted for being one of the few states to repel an attack by the Mongol Empire, and enthroned one of the few female rulers in Islamic history, Razia Sultana, who reigned from 1236 to 1240.

Qutb al-Din Aibak, a former slave of Muhammad Ghori, was the first sultan of Delhi and his dynasty conquered large areas of northern India. Afterwards, the Khilji dynasty was also able to conquer most of central India, but both failed to unite the Indian subcontinent. The sultanate reached the peak of its geographical reach during the Tughlaq dynasty, occupying most of the Indian subcontinent. This was followed by decline due to Hindu rebellions, states such as the Vijayanagara Empire asserting independence, and new Muslim sultanates such as the Bengal Sultanate breaking off.