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.” 32 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. Feuding among knights and peasants was not just a nuisance but a lost opportunity. During Norman rule in England, some genius recognized the lucrative possibilities in nationalizing justice. For centuries the legal system had treated homicide as a tort: in lieu of vengeance, the victim’s family would demand a payment from the killer’s family, known as blood money or wergild (“manpayment”; the wer is the same prefix as in werewolf, “man-wolf”). King Henry I redefined homicide as an offense against the state and its metonym, the crown. Murder cases were no longer John Doe vs. Richard Roe, but The Crown vs. John Doe (or later, in the United States, The People vs. John Doe or The State of Michigan vs. John Doe).