John McCain claimed in his memoir Faith of My Fathers to be descended from Scottish king Robert the Bruce.
Asked by the Guardian to investigate McCain's family history, genealogists and medieval historians described the link to Robert the Bruce as "wonderful fiction" and "baloney".
Claims of Scottish medieval ancestry, [Dr. Katie Stevenson] said, are virtually impossible to prove unless traced through rare documentation. "There are no records of that nature. Any historian will tell you that it's virtually impossible to prove ancestry through the middle ages."
A spokesman for McCain said last night: "The ancestry claim is based upon a genealogical study the McCain family had in their possession, which traced the McCain family roots back to Robert the Bruce." [Link]