Tomara Rajputs were defeated in the twelfth century by the Chauhans of ______.

The Tomara Rajputs, who established their rule over Delhi in the 8th century, were defeated in the middle of the twelfth century by the Chauhans of Ajmer (also known as Chahamanas), under the leadership of King Vigraharaja IV and later consolidated by Prithviraj Chauhan.