Ha! What good timing!
I happen to be doing reserach on wedding customs from around the world for my newest article, and there was mention of why the wedding badn is worn on the left finger.
It started as an ancient Egyptian tradition.
Egyptians believed that the ring finger has the "vein amoris", the vein of love, which runs straight to the heart.
Oh, and on wedding day, the engagement ring is moved to the right hand, so that the wedding band may be placed closest to the heart. Then the engagement ring is placed on top of the wedding band.
I found this info on
World Wedding Traditions.com They have traditions from all over the world. There are some fascinating traditions, and it is amazing how many of them have been incorporated into the modern wedding today.