Originally named the Brecon and Radnor Joint Counties Lunatic Asylum, it was opened amid public ceremony on 18 March 1903, by Lord Glanusk who said of it "everything has been done that human ingenuity could devise for the happiness and safety of the inmates, and under the blessing of God, for their speedy restoration to health.

"[1] Like other contemporary institutions, the asylum was designed to be self-sufficient, and had its own private water, electricity, heating and sewerage systems as well as a considerable agricultural estate on which able-bodied patients worked to produce food for the hospital.

As well as residential wards, the hospital had a large recreation and dining hall, kitchens, workshops "in which the patients [were] encouraged to spend their time profitably", a tailor, bakery, shoe-maker and printing shops as well as 8 acres of market gardens.

NHS management brought a number of innovations, including art and occupational therapy and the integration of the sexes, who had previously occupied opposite sides of the hospital.

The site also became home to the Mid and West Wales College of Nursing and Midwifery and the Powys Drugs & Alcohol Council for substance misuse.