Excerpts from Books and Wikipedia
"This system of trial by jury was not new to England, but it had never before been the law of the land, ordered by the king and enforced by his officials. The Assize of Clarendon changed the nature of criminal acts; it transformed them from local, personal insults into offenses against the king’s peace and even the king himself. Crime was no longer a parochial affair: “If any sheriff shall send word to another sheriff that men have fled from his county into another county on account of robbery or murder or theft,” the assize says, “. . . the sheriff who is informed shall capture them . . . and keep them in custody.” The Assize of Clarendon became the foundation of English criminal law, and the notion at its center is the core of modern Western legislation: the peace of a realm is, in itself, an entity that can be offended; crime is not a personal, but a national, problem. It was a brilliant and nation-changing piece of legislation, pushed through by a man whose restless energy gave him flashes of insight far beyond his century." [Bauer: Renaissance World, p. 129]