Edward II, historical personality with a connection to Wales (Caernarfon)
Edward II
Edward of Caernarvon (as his contemporaries knew him) was the first heir to the England and Wales throne to be styled 'Prince of Wales'. A Plantagonet, he was perhaps one of the most disliked, unsuccessful leaders England has known.Connection: Born in Caernarfon Castle.

Spectacularly unsuccessful monarch.

link by: DdraigGoch
Biography.com

Bio of the First Prince of Wales