I can't helpbut see the connections between the Red Eagle and King Arthur.
Both are natives of a land that was being invaded by what they saw as outsiders. Both untied the natives of said land and then led a war against the invaders which succeeded for a time. Both fell in battle and are foretold to return from the dead in order to return to defend their lands when they are most in need of their hero. And finally, both have a legendary blade that is kept in a stone (even though that part of the legend of King Arthur came after the lady in the lake).
I understand that there are major differences between the two tales, but are there others who can see the generalised connections of the two stories?