The English people became aware of this transformation in the "theory of the state" mainly through the fact that the new tenants-in-chief, bringing with them the ideas in which they had been reared, failed to comprehend the rather complicated status of the rural population on this side of the Channel. To the French or Norman knight all peasants on his manor seemed to be villeins, and he failed to understand the distinction between freemen who had personally commended themselves to his English predecessor but still owned their land, and the mass of ordinary servile tenants. There can be no doubt that the first effect of the Conquest was that the upper strata of the agricultural classes lost the comparative independence which they had hitherto enjoyed, and were in many cases depressed to the level of their inferiors. The number of freemen began to decrease, from the encroachments of the landowner, and continued to dwindle for many years: even in districts where Domesday Book shows them surviving in considerable numbers, it is clear that a generation or two later they had largely disappeared, and became merged in the villein class. Domesday. In this sense, therefore, England was turned into a feudal state by the results of the work of William the Conqueror. But it would be wrong to assert that all traces of the ancient social organization of the realm were swept away. The old Saxon customs were not forgotten, though they might in many cases be twisted to fit new surroundings. Indeed William and his successors not infrequently caused them to be collected and put on record. The famous Domesday Book (q.v.) of 1086 is in its essential nature an inquiry into the state of England at the moment of the Conquest, compiled in order that the king may have a full knowledge of the rights that he possesses as the heir of King Edward. Being primarily intended to facilitate the levy of taxation, it dwells more on the details of the actual wealth and resources of the country in 1066 and 1086, and less on the laws and customs that governed the distribution of that wealth, than could have been wished. But it is nevertheless a monument of the permanence of the old English institutions, even after the ownership of four-fifths of the soil has been changed. The king inquires into the state of things in 1066 because it is on that state of things that his rights of taxation depend. He does not claim to have rearranged the whole realm on a new basis, or to be levying his revenue on a new assessment made at his own pleasure. Nor is it in the sphere of taxation alone that William's organization of the realm stands on the old English customs. In the military sphere, though his normal army is the feudal force composed of the tenants-in-chief and the knights whom they have enfeoffed, he retains the power to call out the _fyrd_, the old national _levée en masse_, without regard to whether its members are freemen or villeins of some lord. And in judicial matters the higher