The third Sultan was Shams-ud-din Iltutmish (), who had the titular name of "Nasir Amir-ul-Mu'minin" () and reigned from 1211 to 1236. He shifted the capital from Lahore to Delhi and trebled the exchequer. He defeated Nasir-ud-Din Qabacha of Multan and Tajuddin Yildoz of Ghazni, who had declared themselves contenders of Delhi. Mongols invaded India in pursuit of Jalal-ud-din Mangabarni who was defeated at the Battle of Indus by Genghis Khan in 1221. After Genghis Khan's death, Iltutmish consolidated his hold on northern India by retaking many of the lost territories. In 1230, he built the Hauz-i-Shamsi reservoir in Mehrauli, and in 1231 he built Sultan Ghari, which was the first Islamic mausoleum in Delhi.