The very first Diabate (originally "i jemba te" = you are unsurpassable) was mentioned in the Sundiata epic in the 13th century*. We are still devoted to our profession and, therefore there are lot of Diabates on the top of the West African music scene. The Diabates in the north-western Mande area (Mali, Senegal) mainly play the kora (a harp-lute), we in the Southeast (Guinea, Cote d'Ivoire and Burkina Faso) rather the balafon (a xylophone).
In my culture, like in many other African cultures, some professions are reserved for certain clans (dynasties) – as a privilege and a duty at the same time -; the training takes place strictly internally, outsiders are not admitted. "Jeliya" is one of these professions. No diplomas are issued; your family name entitles you to practice this profession. Your ability, however, has to be proven every day.
The greatest Diabate-balafonists live among the Tusia, Sambla and Siamou peoples.
*See David C. Conrad (ed): SUNJATA, Hackett Publishing Company Indianapolis/Cambridge, 2004 (pages 46-51)