Shams-ud-din Iltutmish (died 1236) was the third Muslim Turkic sultan of the Sultanate of Delhi and the third ruler of the Mamluk dynasty (or Slave dynasty). He was married to the daughter of Qutb-ud-din Aibak. He became the ruler after fighting Qutb-ud-din's son. He is said to be the greatest ruler of the Mamluk dynasty. He was a member of the Ilebar tribe. The first thing he did after becoming a sultan was make his kingdom larger. He had to defend his empire against Mongol invasions. He also had to deal with Rajputs. Iltutmish stopped the Mongol attack in 1221 A.D led by Chenghiz Khan. He completed the Qutb Minar which was started by Qutb-ud-din Aibak. He also built the Quwat-ul-Islam mosque in Delhi.He died in 1236 A.D. He did not think his sons were be good rulers. He nominated his daughter, Sultana Razia, as the next ruler of Delhi.