The school founded by Richard Stafford Blencowe (RSB), began life in January 1911 as St Philip's School for Boys in a house on the outskirts of Conwy called Gorphwysfa. RSB was initially in partnership with Rev. G. Cooper, an Anglican priest and a former colleague of his at St Christopher's Preparatory School for boys in Bath, where RSB had taught as an assistant master for 2 years after going down from Oxford. Rev. Cooper's wife acted as Matron. Within 2 years, however, the Coopers had left on Rev. Cooper accepting a clerical living in Cheshire and so RSB became sole proprietor and headmaster of the school.
In the early years, there were at most 6-8 boys, but by 1915 the number had risen to 18, and there was a growing need for more accommodation. As a result, the school moved to a large house with extensive grounds outside St Asaph on the Upper Denbigh Road called Bryn Elwy, in January 1916; and as a large majority of parents preferred Oriel (the name of RSB's Oxford College), to St Philips and Bryn Elwy (the other two suggested names), this school became known as Oriel House.
RSB retired in 1952 after 40 years as headmaster, and was succeeded by A.W. Mainwaring-Burton, who in 1969 closed the school and sold the premises, which then became Oriel House Hotel. The hotel was the venue of an annual reunion of Old Orielanians, organised by Mr H. Gough (depositor), which was held on the 2nd Friday of June since 1985. This was a revival of the Old Orielanians Society founded by RSB in 1925.