Until the 17th century, the area was controlled by the McCartan clan. Around the mid-1600s, Patrick McCartan sold lands around Ballynahinch to Sir George Rawdon, agent to Viscount Conway, and Sir William Petty, a surveyor from Hampshire. Before his death in 1687, Petty leased his interest in the land leaving Sir George in sole possession. He built two corn mills and founded the town with a market square. In 1683 Charles II of England granted the town a patent to hold a Thursday market and two fairs every 1 February and 29 June. Settlers from lowland Scotland increased the population and Ballynahinch grew as a market town with the sale of livestock, corn, potatoes and increasingly, flax was being cultivated. Sir John Rawdon, descendant of Sir George and now the Earl of Moira took up residence in Montalto house in Ballynahinch. He made significant improvements to the estate and to the town by promoting the linen market and causing the market house to be built. By the end of the eighteenth century sales in the market were grossing around £300 per week and the town was prospering. Unfortunately it was about to suffer a setback.