While searching for music by Arbeau (16th C) I bumbled into this site. The home page says

"Welcome to the IMSLP / Petrucci Music Library
the free public domain sheet music library.
Online since February 16, 2006 · 14,766 works · 27,753 scores"

Can anybody figure out how to get to the scores that are supposedly on this site? I tried Arbeau and then I tried Johann Sebastian Bach, figuring that they MUST have something by good old J.S. No soap.