Rhuddlan was the home of the Prince of Wales at one time, that is, the independent ruler of Wales, not the titled son of the British king. Its location guards an approach to the mountain heartland of Wales. There have been fortresses at that location continuously since early Celtic times.
The current castle was begun by Henry III’s master mason, who was another of the international elite, and finished by Master James from Savoy. It had a standard 13th century plan of an inner ward and outer ward, both guarded by many round towers. The outer wall was built along the River Clwyd, and the river provided water for an artificial moat around the rest of the outer wall. The inner wall was shaped like a diamond, with double-tower gatehouses on each of the broader sides, and single towers at the “needle” points. The inner ward housed the usual workshops, stables, kitchen, residences and chapel.
During a typical day at the castle, the inner ward would be full of smoke as blacksmiths repaired iron harness and weapon parts and the kitchen brewed and baked. Wagons would be rumbling into the main gate with hay for the horses, who may have grazed in the outer ward.
During the English Civil War, the castle was deliberately turned to ruins so that it could not be used. By then, Wales had become so much part of Great Britain that the castle was no longer useful to guard against rebellion. In case the castle were held by someone on the wrong side of the current stage of civil war, it was too strong for a centralized monarchy to tolerate.
The ruins of Rhuddlan tell us a lot about construction methods of the time. Walls were made thicker not with larger blocks of stone, but with “fill” stone and mortar, somewhat like our particle board or gypsum board construction. Areas that were likely to get battered were built of larger, smoother, harder stone. Likewise, the basic outer facing of a wall was made of fieldstone, cut to lay lengthwise, but not cut to the same shape and size. Masons knew how to do very precise stonecutting, so this was a choice.