The Cyclical Theory of the Rise and Fall of "Asabiyyah"
Ibn Khaldun proposed that nomadic tribesmen form an exceedingly tight "asabiyyah" (tribal cohesion) through their harsh living environment, and that this cohesion is the core driving force by which a tribe can unite and conquer and found a new regime; but once the tribal chiefs enter the cities and found a dynasty, their descendants gradually grow used to a luxurious, settled life, and this original cohesion weakens across the generations, so that usually after three or four generations the dynasty is replaced, through internal disintegration, by a newly rising tribal power of stronger cohesion — a theoretical framework later scholars hold to be the earliest historical-philosophical work to explain systematically the pattern of dynastic rise and fall by structural social factors rather than the mere personal virtue of monarchs.