There is a tide in the affairs of men. It cycles with a period of about three hundred years. During its flood, farms and businesses prosper, and great empires enjoy golden ages. During its ebb, war and famine stalk the land, and states collapse into barbarism.

Chinese population over time

At least this is the thesis of Peter Turchin and Sergey Nefedov, authors of Secular Cycles. They start off Malthusian: due to natural reproduction