Note: The Gnawa groups trace their spiritual lineage back to Bilal ibn Ribah al-Habashi, an Ethiopian former slave who was freed by Abu Bakr (the 1st Caliph) and was appointed by the Prophet as the first muezzin because of his beautiful voice. Most Gnawa musicians descend from enslaved West Africans; their traditional language is Bambara (Bamanankan), which is spoken in some form by around 80% of the population of Mali. It is also spoken in Burkina Faso, Cote d'Ivoire, Senegal, Gambia, and Mauretania. Lomax's note: "4 kettle drums, big black castanets, singing in their own language. Migratory sharecroppers who work for big proprietors on wheat farms, barley, and on the vegetable farms. They receive a 1/4 share."