The Cistercians first settled in north-west Wales in 1186 at a place called Rhedynog-felen near Clynnog Fawr. But within a few years the king of Gwynedd, Llywelyn ab Iorwerth, had persuaded them to move nearer his palace at Deganwy. They were given a site at the mouth of the river Conwy, and Llywelyn gave them a huge endowment of land in Snowdonia and Anglesey.
Successive abbots of Aberconwy played an important part in the negotiations between Llywelyn’s grandson Llywelyn ap Gruffydd and the kings of England in the final years of Welsh independence. When Edward I finally defeated Llywelyn in 1282, he wanted to establish a castle and fortified borough on the strategically-important Conwy estuary. The Cistercian monks were too important to be evicted, but they had to make yet another move, up river to Maenan. Their abbey church in Conwy became the parish church.
More on the Monastic Wales web site.