Cancionero de Medinaceli
The Cancionero de Medinaceli or Cancionero Musical de Medinaceli (CMM) is a manuscript containing 177 pieces of music from the Spanish Renaissance. It was copied during the second half of the 16th century and rediscovered in the 19c in the Library of the Duke of Medinaceli, whence its name. With 100 examples of Spanish secular polyphony, it is probably the most important compilation of its kind after the Cancionero de Palacio. (excerpt translated from the Spanish Wikipedia article)
View the Wikipedia article on Cancionero de Medinaceli.