The generally accepted version of the enclosure movement turns upon supposed changes in the relative prices of wool and grain. The conversion of arable land to pasture in the fifteenth and sixteenth centuries is accounted for by the hypothesis that the price of wool was rising more rapidly than that of grain. The beginning of the enclosure movement, according to this theory, dates from the time when a rise in the price of wool became marked, and the movement ended when there was a relative rise in the price of agricultural products. Before the price of wool began to rise, it is supposed that tillage was profitable enough, and that nothing but the higher profits to be made from grazing induced landholders to abandon agriculture. The agrarian readjustments of the fourteenth century are regarded as due simply to the temporary shortage of labor caused by the Black Death. High wages at this time caused the conversion of some land to pasture, according to the orthodox theory, and from time to time during the next two centuries high wages were a contributing factor influencing the withdrawal of land from tillage; but the great and effective cause of the enclosure movement, the one fundamental fact which is insisted upon, is that constant advances in the price of wool made grazing relatively profitable. It is usually accepted without debate that the withdrawal of arable land from tillage did not begin until after the Black Death, that the enclosures of the fifteenth and sixteenth centuries were caused by a rise in the price of wool, and that the conversion of arable land to pasture ceased when this cause ceased to operate.