continues: As the legend goes, the group arrived at Mobile Bay around 1170, made their way up the Alabama and Coosa rivers and built stone fortifications at several spots near present-day Chattanooga, Tenn.

Dana Olson, an author who has spent decades trying to prove the legend, said circumstantial evidence on both sides of the Atlantic is too compelling to ignore.

"I've traveled all over the country finding these forts. Some of them are pretty well known, but I'm still uncovering some of them," said Olson, the author of "The Legend of Prince Madoc and the White Indians."