The Cantigas de Santa Maria (“Canticles of Holy Mary”) are 420 poems with musical notation, written in Galician-Portuguese during the reign of Alfonso X El Sabio (1221–1284) and often attributed to him. It is one of the largest collections of monophonic (solo) songs from the Middle Ages and is characterized by the mention of the Virgin Mary in every song, while every tenth song is a hymn. The manuscripts have survived in four codices: two at El Escorial, one at Madrid’s National Library, and one in Florence, Italy. Some have colored miniatures showing pairs of musicians playing a wide variety of instruments. http://en.wikipedia.org/wiki/Cantigas_de_Santa_Maria
Black manuscripts - actually on parchment that was painted black - are amongst the rarest manuscripts we have. At the end of the fifteenth century at the court of Burgundy they were popular for a while. Well known is the black hours in the Morgan Library, but barely known is the black manuscript in Brussels (KB 9085) with dance melodies. On a black ground the notes were drawn in silver while the text was written in gold. Underneath the golden text, silvery letters indicate the dance steps.