Founded in 1201 by the local Welsh ruler Madoc ap Gruffydd Maelor,with a nucleus of monks from Strata Marcella. Madoc ap Gruffydd Maelor was a loyal ally of Llywelyn the Great, king of Gwynedd, and Valle Crucis supported the cause of Welsh independence. The abbey was never wealthy but its out-of-the-way location saved it from the worst depredations of Edward I. There was some damage during the Glyndwr uprising but apart from that the abbey was quiet and relatively prosperous.
The church is a fine thirteenth-century building. Possibly because the site was so remote, a lot of the east range of the cloister has survived. You can still see the monks' dormitory and the day stair leading up to it. Under the dormitory is a fine vaulted chapter house, the room in which the community met every day to read a chapter of the rule of the Cistercian order and to deal with any community business.