The old city circles the Mehrangarh Fort and is bounded by a wall with several gates. The city has expanded greatly outside the wall, though, over the past several decades. Jodhpur lies near the geographic centre of the Rajasthan state, which makes it a convenient base for travel in a region much frequented by tourists. The city is also home to several educational institutions, the most prominent being All India Institute of Medical Sciences, Jodhpur, Indian Institute of Technology Jodhpur, Dr. Sampurnanand Medical College, DSRRAU Jodhpur, and National Law University, Jodhpur, and many research institutes, such as Indian Space Research Organisation, Defence Research and Development Organisation, Central Arid Zone Research Institute, Arid Forest Research Institute, and Desert Medicine Research Centre are also located in the city. According to the Rajasthan district Gazetteer, Abhiras were the inhabitants of Marwar and later on the Rajputs established their rule in Marwar. There may have been small settlements before Rathore rule. The Jodhpur city was founded in 1459 by Rao Jodha, a Rajput chief of the Rathore clan. Jodha succeeded in conquering the surrounding territory and thus founded a kingdom which came to be known as Marwar. As Jodha hailed from the nearby town of Mandore, that town initially served as the capital of this state; however, Jodhpur soon took over that role, even during the lifetime of Jodha. The city was located on the strategic road linking Delhi to Gujarat. This enabled it to profit from a flourishing trade in opium, copper, silk, sandalwood, dates, and other tradeable goods.