Diwan Hat Maha Singh founded Diwan Hat on the west of Postarpar, a strategic entry point to the mediaeval port city of Chittagong. Maha Singh was formerly a Diwan of a mughal chief of Chittagong and later elevated to the post of naib subhadar there in AD 1753, in which he continued up to AD 1758. During his tenure in Chittagong the Battle of Palasy was held. He used to hold office in three different places in the Sarkar at Dohazari, Kanchannagar and Sitakunda. The Sitakunda office was known as Singher Haveli. One Birsing also founded the market at Hathazari proper during his time.
An inquiry into the place-name Postarpar may shed light on the unnoticed important role the locality played in a certain period of history of the port City of Chittagong. The Persian word denotes the back or rear. This adjective is also used as a place name in Persian tradition. The place Postarpar in Chittagong was located on the rear of the medieval city in relation to the situation of the port on the bank of the river at Sulakbahar. Transport boats could reach near the spot through a canal from the river Karnafully. This canal was navigable even in AD 1830 when one Captain Pogson traversed it by a boat to reach the cantonment in the city from 'Mug Ghaut' on the river. The remnant of this canal is still known as Arakan Khal. Probably the place name meaning 'crossing the rear' was coined locally as Postarpar in dialectal etymology. The recent discovery of an Arabic inscription mixed with some Persian words in elegant tughra on the gateway of a Mughal type mosque in the locality gives information on the construction of a mosque during the reign of Sultan Ala al-din Husain Shah by one Majlis Khurshid in Chittagong.
The medieval road built by Sultan Fakhr al-Din Mubarak Shah of Sonargaon, the first Muslim conqueror of Chittagong, also entered the city area at Postarpar, and being the junction of water and road network its strategic situation was very important. Maha Singh selected this site to establish Diwan Hat. It continued as a major market place for the inhabitants of the southwestern portion of the Chittagong city for more than two centuries. [Shamsul Hossain]