I am not a genealogy expert, but I disagree with Richardson. My position is that we should be using whatever name a person was called by when living. I suppose it could be a "toss of the coin" in the early second millennium, but a real problem in latter part of the era. There has been a tendency to anglicize names (both given and family) of Europeans, particularly Germans, who immigrated into the U.S. during the 18th and 19th centuries. This has caused confusion, errors, and difficulty is tracing ancestries. In some cases the individuals, themselves, altered their name, but far more often it was done by people who had no understanding of naming practices of the time.