Griot are
oral historians that have been present in
African history just about as long as there have been African languages. In the griot
tradition oral histories are epic length memorized
narratives sometimes turned into
songs.
In royal families young princes are assigned a griot for life who is supposed to document the triumphs and defeats of his charge in order to preserve them. Griots were also companions to their masters (the role of the griot in Sundiata's rise to the rule of Mali is pretty instrumental) as well as advisers and even the official voice of a ruler when royal eloquence was required.
A griot was also instrumental in helping Alex Haley trace his African ancestry to Kunta Kinte. His research was confirmed by the griot of his village.