Riwal Mawr Marchou,
Prince of Domnonée
Deroch I map Riothamus' son was Riwal the Great Knight. He is said to have hailed
from Britain and to have emigrated to Brittany with a large number of followers.
This, however, was probably invented to explain his supposed British Dumnonian
ancestry; though it is possible he held lands on both sides of the Channel. In
Brittany, Riwal found it politic to pay homage to King Lothaire I of the Franks,
as well as his cousins in Cornouaille, in order to secure his position.
Fracan of Cerniw settled in Domnonée, he quickly had
a set to with his new monarch. Riwal claimed to have a much swifter horse than
Fracan, but the latter could not agree. They organised a race to decide whose
beast was the best, but the new arrival's jockey fell and was nearly killed.
Luckily, Fracan's son, St. Winwaloe was able to heal him. Riwal may have been
impressed by this saint's miracle working for he became a patron of the church
and gave much land to his cousin, St.Brioc. Riwal probably died around AD 520
and was succeeded by his son as Deroch