I wanted to closed the discussion about the names Feitje and Fietje in
Holland and give a answer to Nick Landau about this names.
Feitje is derived >from the Yiddish-German name Fegele or Vogele. We don't
find this name in Dutch name books.
Fietje is a short form of the name Sofia (Sophia) .
Sofia - Sofietje - Fietje.
If you look in every Dutch name book you find this explanation about Sofia / Fietje.
I look into " Prisma Voor-namen" a dictionary of given names by J.van der
Schaar, Het Spectrum 1992 Utrecht, on page 329.