Originally intended to be sited at Mountnorris, South Armagh, the turbulent situation in Ulster at the time led to a move to the relative safety of Armagh city. Despite this, an early headmaster of the school, John Starkey, and his family, were drowned by insurgents during the 1641 Rebellion. The school arrived at its current site on College Hill in the 1770s. A boys' school from its inception, the Royal School was amalgamated with Armagh Girls' High School in 1986 to become co-educational.