h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

He was about 50 years old when he started the rebellion, the wealthiest Welshman of his time, who was trained in law and arms in England. The quarrel which led him to rebellion against King Henry IV was over ownership a small piece of land between him and his neighbour (a case of medievial neighbours from Hell). As Lord Grey of Ruthin, his neighbour, was a personal friend of the King the judgement went against Owen. When Owen went to London to appeal he was humiliated by the Kings court and therefore went to arms against what he saw as injustice. He soon gathered an anti English movement basing himself at Snowdonia and fighting a guerilla war which the King found hard to subdue. In one notable action Owen caputured Lord Grey and following the ransom for his life bankrupted him. Owen fought for some 12 years most of the time controlling Wales, with only a few castles under English control but by 1412 a young Prince Henry (later to be King Henry V) forced the Welsh troops to slowly, one by one, to surrender. Owen and a small band escaped from the English and were never found. It is said that he and his men are asleep on their arms in a cave in the Vale of Gwent, waiting for another day to sally forth against the English.

Wasn't there some kind of 'prophecy' about his return; when up and about one morning, he remarked to a passing friar that he was up early and was told, 'It is you who are too early'- implying his involvement in future events.