This Lithuanian site even lists other forms of Michael...
in reply to a message by Lucille
and Maciej is not one of the forms listed. See here:
http://day.lt/vardai/Mykolas
I think the person who told you about Maciej being a Lithuanian name was probably mistaken.
http://day.lt/vardai/Mykolas
I think the person who told you about Maciej being a Lithuanian name was probably mistaken.