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

Gruffydd ap Llewelyn was the son of Llewelyn Fawr. As a young man, he was taken hostage by his step-mother's father, King John of England and held hostage for several years. While in captivity, he witnessed the deaths of all other Welsh hostages, many of whom were children.

Gruffydd was angered by his father's decision to make Davydd his sole heir, beleiving that his should have split his lands between both of his sons according to Welsh custom. Llewelyn, however, did not want his lands separated.... he wanted them to remain a united kingdom. As a result, Gruffydd later finds himself in civil war against his brother, Davydd, within months of his father's death. Gruffydd was then taken prisoner by Davydd and made a prisoner of the king of England. During an escape attempt in the Tower of London, Gruffydd fell to his death.