The more you know...
I learned something new today. In English (British) language history, if someone has "Fitz" in their last name, it denotes a male who is illegitimate to the aristocracy.
Fascinating!
Fitz: used in compound names, to indicate illegitimate paternity of the sons of kings and princes of the blood; as, Fitzroy, the son of the king; Fitzclarence, the son of the duke of Clarence.