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

Llewelyn Fawr is credited with uniting Wales. He was the first Welsh prince to accept homage from all the other princes of Wales. He was highly respected by both his people and his enemies. When the novel begins, Fawr has come to the end of his life and has left his lands and his title to his son, Davydd, despite laws that say all Welsh sons should inherit equally. His decision leads to a civil war between his sons, Davydd and Gruffydd.