Some of what historians have written about pre-Imperial Mali is based on oral tradition collected since the late nineteenth century. Much of the tradition focuses on the "Epic of Sunjata" a series of tales about early Mali that griots assemble into longer versions. There are several of these versions in print, the most famous of which is that of D. T. Niane, thanks to its lively narrative style and early translation into other languages. Niane's work, however, is not a literal translation of an original oral discourse, though it is surely largely based on tales told by a certain Mamadou Kouyate of Keyla. Rather, it is a reworking in literary form of Kouyate's tales. More literal versions of the tradition have since been published in French, English and Mandinka versions.