One of the worst famines in the region's recorded history occurred in the 18th century. According to John Iliffe, "The worst crises were in the 1680s, when famine extended from the Senegambian coast to the Upper Nile and 'many sold themselves for slaves, only to get a sustenance', and especially in 1738–1756, when West Africa's greatest recorded subsistence crisis, due to drought and locusts, reportedly killed half the population of Timbuktu."