Ajaipal Chauhan founded Ajmer in the seventh century. He constructed a hill fort "Ajay meru" or the " Invincible Hill ". He established the Chauhan dynasty which continued to rule the country while repeated waves of Turkish invasions swept across India. When you visit Ajmer today it is difficult to imagine this small city was at one time the seat of power of the Chauhan Dynasty. It was from Ajmer that the last Hindu ruler of Delhi, Prithviraj Chauhan III, controlled a major part of Northern India. The legendary Prithviraj lived hereand became a force to reckon with. His exploits are related with great wonder and sometimes disbelief.
The Chauhans dominated Ajmer for many years and it was only towards the end of the 12th century that Prithviraj was killed and Ajmer was conquered by Muhammad of Ghor, founder of the Delhi Sultanate, in 1193. That Changed the history of this region totally. The Importance of Ajmer diminished with the death of its most valiant ruler and Ajmer passed under the Delhi Sultanate. Later the Descendant of this clan established the Chauhan Clan of Ranthambore in 1194. The internal government of Ajmer, however, was handed over to the Chauhan rulers upon the payment of a heavy tribute to the conquerors.
From then on Ajmer saw may upheavals and remained feudatory to Delhi until 1365, when it was captured by the ruler of Mewar. In 1509 Ajmer became a source of contention between the Maharajas of Mewar and Marwar, and was ultimately conquered by the Marwar ruler in 1532. Ajmer was conquered by the Mughal emperor Akbar in 1559and gave Ajmer the status of a full-fledged province. He also used Ajmer as a base for his operations in Rajputana. It continued to be in the hands of the Mughals, with occasional revolts, until 1770, when it was ceded to the Marathas. From that time up to 1818 Ajmer was the scene of an ongoing struggle, being seized at different times by the Mewar and the Marwar maharajas, from whom it was often retaken by the Marathas. In 1818 the Marathas sold Ajmer to the East India Company for 50,000 rupees. Since then Ajmer has enjoyed stable governance, although during the 1857 War of Independence some Indian sepoys at the garrison in the nearby town of Nasirabad joined the revolt. Under the British Raj, Ajmer was governed by an Agent to the Governor General overseeing Rajputana. After independence in 1947, Ajmer retained its position as a centrally administrated state under a Chief Commissioner for some time. Ajmer was eventually merged with the State of Rajasthan in the 7th and last phase of political integration of Rajasthan as its current form on 1st Nov. 1956. Later with due considerations towards Ajmer's political, geographical and strategic value, vital and important government offices of state were opened in the district like Board of Revenue (Raj.), Rajasthan Public Service Commission, Directorate of Ayurveda Dept., Board of Secondary Education (Raj.); Besides other important institutes funded & run under GOI like Central Board of Secondary Education, Regional Institute of Education, Rashtriya Military School and Central University of Rajasthan.