I made a mistake teaching my course on precolonial African history this past fall. I vowed (to myself) to be absolutely honest. I decided to admit to students how little historians know for certain about much of Africa's early history. I focused on the evidence, emphasizing how little there is for determining what occurred several centuries ago—let alone 2000 years ago—in sub-Saharan Africa. I gave one lecture—downright sterling, I thought—in which, in the first part, I taught about “Bantu Expansion” as I had done in my first year on the job, way back in 1976. I had read Roland Oliver's 1966 article in the Journal of African History, which had made everything clear to me once upon a time.
With that as a basis I laid out an entire scheme about how these humans, who spoke related languages, had populated nearly all of sub-equatorial Africa since the beginning of the modern era. I had maps on overhead projection (copies handed out) showing when the Bantu migrated where; I spoke of the evidence for it all, even reading from Ptolemy's Geography and the Periplus of the Erythraean Sea; and recalled how clear it all was to myself and the students, who wrote down nearly every word and made notations on the maps.
Then, in the second part of the lecture, I talked about how incorrect it all was (student pens here coming to rest)—how our reading of some of the linguistic evidence was faulty, how we read things into Ptolemy and the Periplus because they fit the scheme, and how subsequent archeological evidence has simply proved most of the neat scheme wrong. I concluded with an honest, if pessimistic, note that, because of the paucity of evidence, there simply is a lot about early African history that we will not be able to know.