St. Mary’s Hospital is located in the Phoenix Park, close to the Chapelizod entrance to the park. St Mary’s Hospital was built in 1769 and was originally the Royal Hibernian Military School. The building was subsequently developed as a hospital by the Irish Army and in 1948 the hospital was transferred to the Dublin Health Authority and developed as a Chest Hospital. In 1964 the hospital became a facility for older people and today primarily provides accommodation to dependent older persons.