Ars Subtilior. Music of the late Medieval period  
   French Secular Music of the Late 14th Century.
   http://www.pacificnet.net/~garyrich/subtilior/

Classical MIDI Connection: the Renaissance Period  
   Indexed by composer, where known.
   http://midiworld.com/cmc/renaissa.html

Classical MIDI Connection: the Baroque Period  
   Classical MIDI Connection's files for hundreds of Baroque pieces, listed by composer; major composers such as Bach and Handel have their own special sections
   http://midiworld.com/cmc/baroque.html

Early Music at MidiWorld  
   200+ medieval, renaissance, and early baroque files.
   http://midiworld.com/earlymus.htm

Scores and MIDI files  
   Music for recorder by Bach, Rosenmueller, Ravenscroft, Simpson, and Praetorius.
   http://www.saers.com/recorder/mondrup/

Classical Music Archives: Early Music  
   Special page for early music, with over 1200 MIDI and MP3 files for pieces by over 220 composers. [requires JavaScript]
   http://www.classicalarchives.com/early.html

Music of the 14th Century  
   Machaut, De Perusi, Solage, Trebor
   http://academics.vmi.edu/english/med_midi.html