 In 1191, he invaded the territory of Prithviraj III of Ajmer, who ruled his territory from Delhi to Ajmer in present-day Rajasthan, but was defeated at the First Battle of Tarain.The following year, Mu'izz al-Din assembled 120,000 horsemen and once again invaded India.Mu'izz al-Din's army met Prithviraj's army again at Tarain, and this time Mu'izz al-Din won; Govindraj was slain, Prithviraj executed and Mu'izz al-Din advanced onto Delhi.