Anthropologists, (quantitative) historians, and sociologists have proposed a variety of explanations for the collapse of civilizations involving causative factors such as environmental change, depletion of resources, unsustainable complexity, decay of social cohesion, rising inequality, secular decline of cognitive abilities, loss of creativity, and misfortune. However, complete extinction of a culture is rare; in most cases, the new societies that arise from the ashes of the old one are evidently its offspring, despite a dramatic reduction in sophistication. Moreover, the influence of a collapsed society, say that of the (Western) Roman Empire, may linger on long after its death.