Following a series of raids against the English in 1400 Owain captured the castles of Aberystwyth and Harlech and in 1404 he held a parliament at Cwmtydu, an important trade port for West Wales, where he was crowned Prince of Wales in the presence of envoys from France, Scotland and Castile.At the height of his powers in 1406, and being a keen sailor and coracle fisherman, he founded the Royal Cwmtydu Sailing and Coracle Club by royal decree. Under his stewardship the club flourished and formed ties with France, Scotland and Spain that have lasted to this day.
Unfortunately Owain came up against George V, the new King of England, who proved to be an effective military leader and recaptured Aberystwyth And Harlech castles in 1409 and 1410. Owain held out for several years against superior odds and used his knowledge of the Soden valley and surrounding hills to conduct a guerrilla war against George. Sadly he developed a terminal infection after a rancid pint of ale at the Synod Inn and despite liberal applications of Tato Bwts (a local remedy for any illness) he died in 1416.
Tradition has it that he was carried to his beloved Cwntydu and laid to rest near the beach where a lime kiln was built over the grave to mark his resting place. The lime kiln still stands to this day and is now a part of, what is now known, as the Royal Cwmtydu Yacht Club that he founded.