I recently found out that my Aunt Pauline's real name is Appolonia, and my aunt Emily is really Josephinia. The other Polish names i can't even spell but they were all Americanized when the kids started school.
My dad's name was Jack. But when he applied for a passport, he also got a copy of his birth certificate and it said "Jake". His Russian father had a thick accent so when the census bureau asked for dad's name, he said "Jeck" or something similar, so it was put down as Jake. He was our Jumpin Jack Flash, regardless!!! Rock On Dad!