don't mind me, I'm just lurking, but they wore exactly the same thing that the adults did. If you can stand it, Simplicity used to have an infants/toddlers pattern that had the suit that the Infant Edward VI (if I got my number right) was painted in.
no subject
Holbein -- child approximately 2
http://www.wga.hu/art/h/holbein/hans_y/1535h/05edward.jpg