ForeverAmber, in answer to your question I can only firstly tell you about Rhodri Mawr and Cadwaladr from my perspective, though this has given me a challenge to find out more!!
Rhodri Mawr, was and is referred to as the first Prince of Wales. The Warrior King that that united many tribes and kingdoms of Wales under one rule. Lead his country against many Viking invasions, often very successful. He is remembered for slaining the great Viking leader Gorm. He died in battle against an English invasion.
Two centuries before Cadwaladr ruled as king of the whole of the United Kingom, as by Rhodri's time, the Britons (Welsh descendants) had been pushed back into the heart of Wales.
Historically Rhodri is reknowned for being the first Prince of Wales, but not technically. Though I should point out that prince, or even princess was never used as a Welsh title before Rhodri's time. The English gave Rhodri his title.
Rhodri is known as a warrior, leading his country against invasion. Cadwaladr is known as a compassionate king, helping peasants in the time of plague, living as poorly as his subjects, was recognised as a martyr and canonised.