Very interesting article; I've come across the Fulani 'Jihad' and its side-effects on Nigerian states in the C19th during a previous research job for writing a book, but the complexity of inter-tribal mini-empires and their leadership is largely new to me. The overall picture reminds me of the sudden rise and fall of tribal empires in the northern Central Asian region, what is now central Siberia, before and during the Genghis Khan era - a coalition of tribes under a charismatic leader with military skills would suddenly pop up, sweep all before it, then collapse after a generation or two. (The same had happened there in the earlier post-Roman centuries, with the rise and fall of the Turks and Avars - and it affected European history as the losers tended to head West and end up in Ukraine and Moldova, as a threat to the settled states of east-central Europe eg the Eastern Roman Empire.)
But in the case of Asian turbulence, there was more long-term interest and - often later not contemporary - literary accounts of it in European and Chinese records due to how these wars and population shifts impacted on major civilizations, albeit centuries later - eg the question of whether the Huns in the C5th were migrating 'Hsiung-nu' from the Chinese frontier and how the C7th Turks from central northern Asia ended up in Iran and Mesopotamia in the 1050s and Gallipoli by 1354. West Africa in the C19th was largely outside European interests except for the French. And the surviving 'states' / personal military fiefdoms that these W African leaders created came up in the 1870s-90s against a vastly more technically advanced European power, ie France, and were swept aside (as the British were to do to the more settled, urbanised states of the Hausa in N Nigeria and the Yoruba in the South). This begs the question of how things would have developed had one of these Sahel regimes both stabilised and been centred in an area that France was not interested in - or the dynamic of French expansion had not been by land S from Algeria but focussed elsewhere, eg on Nigeria if the British had left that alone and concentrated on East Africa. (Or France not Belgium had swallowed up the Congo?). Could a stabler W African tribal army under a viable dynasty of a succession of capable adult leaders adopted Western weaponry and semi-modernised , with a capital on the R Niger to attract trade, as a western equivalent of Menelik in Ethiopia? Parallels with what could have happened in Mexico in the C16th long-term if the Aztecs had dealt with Cortez ruthlessly and become a power that Spain was wary of tackling again but which it traded with to get gold - or an Inca state in Peru (both more administratively advanced than W African tribal states) that had seen off Pizarro?
