John Doe

HELP!!!
This is a serious question…

I’m trying to find the origin of the term “John Doe” being used as being everyman, or why it is used as the name of unknown persons?

Thank you,

Tech Teacher

http://www.straightdope.com/classics/a2_168a.html

Don’t overlook followup thread at
http://boards.straightdope.com/sdmb/showthread.php?threadid=138266&highlight=john%2Bdoe%2Bstraightdope

Further discussion here.