The condition of the serf appears to have been, under these circumstances, inevitably connected with the "barter economy" as applied to the renting of land. A farm cannot be moved, and in medieval conditions its products mainly had to be used on the spot. If the serf was to use and enjoy the land, he had to stay upon it. Having no money he had to pay in labor or in products, for its usufruct. In those times the powerful man, politically, was also a wealthy man whose wealth consisted of landed estates. Between the landlord and the serf existed a lasting relation, inherited rather than voluntary, but similar in its conditions to the renting contract. The villein had the use of the stock, pastures, fields, woodlands, provided he kept them undiminished and undestroyed to transmit to his children. Under such conditions there was great fixity of economic relations. While in some respects this was a happy condition, it had its disadvantages. The renting contract, in connection with a fixed rotation of crops and some communal modes of cultivation, hindered improvements. The more intelligent cultivator could not change his methods for the better. It may be seen not only that the use of money on a medieval manor was slight, but that the conditions for the growth of the money habit were most unfavorable. The terms of agricultural contracts, the modes of speech, the habits and thought of the mass of the people, were therefore determined by the conditions of the barter economy. A change in these respects was slowly worked by forces originating outside, in a very different industrial environment. [Sidenote: Contrast between city wealth and feudal estates in the Middle Ages] 4. _With the growth of cities developed a new class of wealthy men and a new view of wealth._ The student of history knows of the conflict that grew up during the Middle Ages between the cities and the landed aristocracy. It found its cause in economic conditions. There were obvious differences between the wealth of the feudal landlords, and the wealth that grew up in cities. One must be used mostly on the spot, the other can be moved. The fruits of one are perishable for the most part; the fruits of the other can be kept for a longer period. The methods of agriculture are exceptionally stable; production by handicraftsmen is dependent on the peculiar skill of the workman, giving greater room for invention and a premium on skill. The one industry may be carried on by servile labor; the other can be efficiently followed only by free workers having the ambition to excel. [Sidenote: Money thus more used in city trade]