Wales and England were countries governed by different laws and customs. The latter had been unified under the merciless hands of first Norman and then Angevin kings. Wales was governed by many lords and its people lived in villages rather than towns.
In 1240 Llywelyn the Great died. He had brought a greater degree of unity and cohesion to the land than any previous lord. Llywelyn had married Joanna, illegitimate daughter of King John. They had two sons Gruffydd and Dafydd. According to Welsh law each should have shared in their late father's estate, but Llywelyn ensured that the lion's share passed to Dafydd. To make doubly sure Dafydd imprisoned his elder brother in Cricieth.
In May 1240 Dafydd attended the council of Henry III to do homage for the lands of Gwynedd together with the other nobles of Wales. Whilst quite happy to recognise Dafydd as Llewelyn's heir, Henry had no intention of allowing him to retain Llywelyn's conquests. Some, like Cardigan, were seized by force; others became a matter of negotiation.
Dafydd dragged his feet in the arbitration process until Henry's patience collapsed. In August 1241 the King pressed into North Wales from Chester with his army. A summer drought made it far easier for the English to force Dafydd to surrender without a battle being fought. The terms of the peace were severe.
Henry demanded custody of Gruffydd, threatening to set him up as an independent prince within North Wales. All Llewelyn's conquests were returned to their previous lords and Dafydd was fined, losing the cantref of Tegeingl (roughly the land to the east of the river Clwyd).
In 1244 Dafydd's fortunes revived, when his brother Gruffydd died trying to escape from the Tower of London. With his rival dead and buried, the other Welsh chiefs rallied to his side.
By the summer of 1244 Dafydd was at war with England. Henry had built a new castle at Dyserth some 3 miles east of Rhuddlan. This came under serious assault from the Welsh, but the foolish Henry dithered for a year before coming to its aid.
The English army moved from Chester on 20th August 1245 and pitched camp at Degannwy on the east bank of the river Conwy on 26th. And there Henry remained building a mighty fortress, whilst his men starved and shivered. A brutal conflict ensued across the Conwy. The English ransacked the Cistercian house of Aberconwy, located near the site of the future Conwy Castle. The Welsh captured an Irish vessel stranded in the estuary, depriving the English of 60 casks of wine. The English butchered Welsh prisoners and the Welsh retalliated in equally savage fashion.
By October 1245 Henry had to withdraw his men to England, rather than remain at Degannwy and suffer the inevitable losses through a bitter Welsh winter.
But in February 1246 Dafydd died leaving neither son nor daughter. Instead the lordship of Wales was to pass to a son of his dead brother, Gruffydd. The time of Llywelyn the Last had come.