Corwen is best known for its connections with Owain Glyndŵr, who proclaimed himself Prince of Wales on 16 September 1400, from his nearby manor of Glyndyfrdwy, which began his fourteen-year rebellion against English rule.
In the Owain Glyndŵr Memorial Hall are artifacts associated with the man himself: a copy of the Pennal Letter to King Charles VI of France, a document of 1405 ratifying the terms of a 1404 treaty between Owain and the French, a letter confirming the appointments of Owain's Chancellor, Gruffydd Young and Owain's brother-in-law, John Hanmer as Ambassadors to the French Court, pictures of the Parliament house in Dolgellau, a portrait drawn from Owain's seal, and a replica of this seal.
Gruffudd Fychan II (c. 1330-1369), Lord of Glyndyfrdwy and Cynllaith and father of Owain Glyndŵr, Prince of Wales
After their homes at Sycharth and Glyndyfrdwy were burned in 1403, they lived, among other places, at Harlech Castle, which was taken in 1409 by the young Henry of Monmouth.