So portentous a title as I have contrived for tonight's lecture ought to come furnished with an appropriately bombastic beginning. In fact, it does not. Instead of concentrating on a beginning, I thought that we might more profitably focus our attention on the beginning, that is, on a time long before the sophisticated legal/administrative system of England's high middle ages had evolved. It will be interesting to get what peeks we can at the jurisprudential assumptions of, say, preconquest Englishmen. As Tom Green has recently demonstrated in his book on the criminal jury, these assumptions could exhibit a durability that had functional consequences for many centuries. If through the jury they could prevail against contrary official versions of what the substantive law was, as Green has shown, how much more potent could they be when the government was not inclined to oppose their effectuation?