At first he got what he wanted by a simple process of exchange. The smith who han not the time to look after land or cattle was glad to take meat or grain from the farmer in exchange for an azc or a plough. But as more and more goods which had no fixed exchange value came on the market, exchange becamc too complicaled to be salisfactory. Another problem arose when thosc who madc things wanted to get stocks of wood or leather, or iron, but had nothing to offer in exchange until their finished goods were ready.