Out of curiosity I did a bit more digging since my last post. Matthau was evidently quite inventive when talking to reporters. From the link below:
Matthau made up stories so often that family and friends, as well as interviewers, never knew when he was pulling their leg, so details of his early life are questionable. He once said his mother was a gypsy and his father (or grandfather) was an “Orthodox priest in Czarist Russia, who was removed after he claimed that the Pope was infallible”. According to his official website, www.matthau.com, among the tall tales he told about himself were that “he was in line of succession to the throne of England...”.
http://www.tcm.com/this-month/article/138987%7C0/Walter-Matthau-Profile.html
Everything I have ever heard about him points to him being a complete maniac. I love that he was telling Very Important Hollywood Reporters all this crap, ha.
Freegards