Who is Llewelyn Fawr from Falls the Shadow and what is their importance?

Llewelyn Fawr was the first man to unite Wales. Greatly respected by his people, Llewelyn Fawr has died and left his lands and title to his son, Davydd. His wishes, however, directly conflicted with the laws declaring all Welsh sons should inherit equally. Fawr's actions lead to civil war after his death between his son Davydd and Gruffydd and his sons.