Documents preserved at Gloucester Cathedral state that Chertsey Abbey misappropriated, and was later compelled to yield up, a church at Cardigan which had been granted to Gloucester by Gilbert de Clare (d. 1114) previous to the establishment of the priory. The Brut y Tywysogion states that De Clare granted Cardigan Priory to the Gloucester Abbey prior to his death; ergo its founding date is set c.1110-15. Around 1164, Rhys ap Gruffydd, Prince of South Wales, conquered Cardigan and brought it again under Welsh rule, and by a grant confirmed the gift of the then existing priory cell of Cardigan to the Benedictine Black Monks of Chertsey Abbey, at which time the Gloucester monks were sent away. During the Clares' time, it was dedicated to the Trinity; in Rhys's time, it was dedicated to St. Mary.
The priory dissolved in 1538 after which time it was converted into a mansion and granted to Bisham, Berkshire, and subsequently to William and Mary Cavendish (1539/40). In the mid 17th century Cardigan Priory was the favoured home of Katherine Philips, known as "The Matchless Orinda". In 1922 it was re-opened by Dame Margaret Lloyd George as the Cardigan District and Memorial Hospital.
The priory was set on 200 acres which adjoined Cardigan Castle. The grounds and buildings extended along the River Teifi. The Bishops of St Davids lived in one of the buildings when they visited Cardigan, which may have coincided with problems noted by the abbot of Chertsey in 1433/4. In a 1599 map, the priory church is represented as cruciform in shape, while in Blaeu's map of 1646, the cruciform includes an adjoined chapel, probably the chantry chapel of Sir John ap Jevan. The Church of St. Mary and the priory were two separate buildings.
- The Athenæum: a journal of literature, science, the fine arts, music, and the drama (Public domain ed.). J. Francis. 1906. pp. 476–. Retrieved 18 March 2012.
- Pritchard, Emily M (1904). Cardigan Priory in the olden days (Public domain ed.). Heinemann. pp. 7, 15, 17, 43, 44. Retrieved 18 March 2012.
- "The Priory". Coflein Database Record. Royal Commission on the Ancient and Historical Monuments of Wales. Retrieved 28 November 2016.
- Thomas, Thomas (1822). Memoirs of Owen Glendower, (Owain Glyndwr): with a sketch of the history of the ancient Britons, from the conquest of Wales by Edward the First, to the present time, illustrated with various notes, genealogical & topographical (Public domain ed.). Printed for the author (rector of Aberporth, Wales.) by J. Potter. pp. 198–. Retrieved 18 March 2012.
- "Cardigan Timeline". welshabbey.org.uk. Retrieved 19 March 2012.[permanent dead link]
- Heale, Martin (2004). The dependent priories of medieval English monasteries. Boydell & Brewer. pp. 76–. ISBN 978-1-84383-054-2. Retrieved 18 March 2012.