Y rhew was a maintained peace arrangement between the Ordovices of Powys and the Silures of Brycheiniog during the Early Iron Age. The term translates as "the frost."

The Beulah Law emerged in 627 BC when unchecked ambition destroyed a village between Powys and Brycheiniog. One goat for every five people, never more—a measure bought with blood and remembered across fifteen centuries through two chilling words: Remember Beulah.