It was Prime Minister Sir John A. Macdonald who first began planning a permanent force to patrol the North-West Territories after the Dominion of Canada purchased the territory from the Hudson's Bay Company. Macdonald received his inspiration for the creation of the RCMP from the Royal Irish Constabulary, the quasi-military police force of Ireland from 1822 to 1922. Reports from army officers surveying the territory led to the recommendation that a mounted force of between 100 to 150 mounted riflemen could maintain law and order. The prime minister first announced the force as the "North West Mounted Rifles". Despite being originally created with a primary purpose to clear the plains, the Prairies, of Indigenous people officials in the United States raised concerns that an armed force along the border was a prelude to a military buildup. Macdonald then renamed the force the North-West Mounted Police (NWMP) when formed in 1873.