The original owner of the new site, a welsh lord; Cadwallon ap Madog, was killed by the English Sir Roger Mortimer not long after the refoundation, and patronage of the abbey was transferred to him. The community subsequently suffered over many years for it’s conflicted loyalties, and twice in the 13th century, abbey granges were burnt by Royal soldiers and in 1231 the abbot was also fined £200 for aiding the Welsh cause. In the early 13th century, the construction of what would have been a spectacular and spacious abbey church were embarked upon, equal in scale to many a cathedral. But this project was abandoned shortly after the completion of the 14 bay nave. The ongoing political and social troubles were undoubtedly the cause and the abbey fortunes diminished even further during the significant damage inflicted during the uprising of Owain Glyndŵr from 1401. The monastery intended to support 60 monks at the outset, only had three in residence by the time of the dissolution.
The Dissolution and beyond
The abbey was closed in 1536 and became the possession of the Fowler family who built a house on the site. In 1644, during the English Civil War, the house and any surviving monastic structures were wrecked and probably destroyed in the fighting. What little remains was excavated in the 19th century and is open to the public. Only fragmentary stretches of the nave of the church remain visible and a modern grave slab within such commemorates the last native Prince of Wales, Llewelyn ap Gruffydd, who died in 1282 and was buried in the church.
In the nearby village church of Llanidloes, there are a series of 13th century arches, and other features, believed to have been taken from the abbey church and re-erected there in 1542.