The Cistercians, as you may know, liked to build their monasteries in remote places, and they don't come a lot more remote than Ystrad Fflur (the Vale of Flowers) which latinised becomes Strata Florida.
It is still a peaceful and, in its own understated way, beautiful spot. The only thing that jars is the roofs that Cadw have perforce erected to protect the very fine medieval tiles in the chapels in the north transept.
For opening times, admission prices, etc. please see Cadw's official site.
Strictly speaking the abbey was founded in 1164 by the Cambro-Norman Knight Robert Fitzstephen, who allowed Cistercian monks from Whitland Abbey to found a religious settlement at Hen Fynachlog (which means the Old Monastery), about 2.4 km (1½ miles) from the present site near Old Abbey Farm (map). However, later in 1164 Fitzstephen was overthrown by the Welsh prince Rhys ap Gruffydd who is thus regarded as the true patron of the monastery.
The exact date of the move to the current site is not known, but it seems likely that it happened sometime around 1184 when Lord Rhys granted a new charter to the abbey.
During the next two centuries very little happened. Lord Rhys was buried here, along with eleven other princes of the Welsh royal house of Dinefwr of Deheubarth, and many of the grave stones can still be seen.
Then in 1401, Henry IV turned up and evicted the monks as they were deemed to be sympathetic to Owain Glyndwr's rebellion. The buildings were turned into a military base and used for campaigns against the Welsh rebels in 1407 and 1415, before eventually the monks were allowed to return. After that, nothing much happened until the abbey was dissolved in 1539 and most of the buildings were demolished.