"But Elias did propose an exogenous trigger to get the whole thing started, indeed, two triggers. The first was the consolidation of a genuine Leviathan after centuries of anarchy in Europe’s feudal patchwork of baronies and fiefs. Centralized monarchies gained in strength, brought the warring knights under their control, and extended their tentacles into the outer reaches of their kingdoms. According to the military historian Quincy Wright, Europe had five thousand independent political units (mainly baronies and principalities) in the 15th century, five hundred at the time of the Thirty Years’ War in the early 17th, two hundred at the time of Napoleon in the early 19th, and fewer than thirty in 1953. The consolidation of political units was in part a natural process of agglomeration in which a moderately powerful warlord swallowed his neighbors and became a still more powerful warlord. But the process was accelerated by what historians call the military revolution: the appearance of gunpowder weapons, standing armies, and other expensive technologies of war that could only be supported by a large bureaucracy and revenue base. A guy on a horse with a sword and a ragtag band of peasants was no match for the massed infantry and artillery that a genuine state could put on the battlefield. As the sociologist Charles Tilly put it, “States make war and vice-versa.” Turf battles among knights were a nuisance to the increasingly powerful kings, because regardless of which side prevailed, peasants were killed and productive capacity was destroyed that from the kings’ point of view would be better off stoking their revenues and armies. And once they got into the peace business—“the king’s peace,” as it was called—they had an incentive to do it right. For a knight to lay down his arms and let the state deter his enemies was a risky move, because his enemies could see it as a sign of weakness. The state had to keep up its end of the bargain, lest everyone lose faith in its peacekeeping powers and resume their raids and vendettas."