Ibn Khaldun

Ibn Khaldun was a North African statesman and judge who served a succession of rulers from Fez to Granada to Cairo, negotiated with Tamerlane outside besieged Damascus, and withdrew for four years to a castle in Algeria to write the Muqaddimah, the introduction to a universal history that became more important than the history. It proposes a science of civilisation: that dynasties rise on the group solidarity of the desert, soften in the cities, and fall within three generations to the next hard people from the margins. Toynbee called it the greatest work of its kind by any mind in any time or place.