I can't remember if I've linked this here before or not, but here it is (again?) anyway -- a beautiful 13th-century French manuscript songbook, full of interesting pieces by an array of trouvères:
Recueil de chansons du XIIIe siècle, avec musique notée I'm contemplating attempting to transcribe a song, mostly as an exercise in assessing exactly how much I don't know about medieval French... :P