No country could compare with England, during the Middle Ages, for the production of wool. From the twelfth century onwards wool was almost the only export and the principal source of wealth for landowners and farmers. So important a trade was bound to receive the attention of Chancellors in search of a new tax. Accordingly, early in the thirteenth century, a system was devised by which no wool could possibly be exported until it had contributed its quota to the royal treasury. Wool, as well as some other raw materials, such as skins, lead and tin, had to be brought for sale to an appointed place called the Staple, where the trade was under the superintendence of a special corporation whose seal must appear on every bale. The Staple was at first fixed at Bruges, the chief seaport of the Flemish cloth manufacturer, but during the reign of Edward III, it was moved to England, and then finally, in 1390, established at Calais. Thither every dealer was obliged to carry his bales by certain approved routes, through Boston, London, Sandwich, Winchester, or Southampton, and these towns became subsidiary centres of the Staple. _Staple Inn_, in Holborn, was an inn for merchants of the Staple before it became a resort for the lawyers. In the end the merchants of the Staple grew into a ring of powerful monopolists, who controlled prices, regulated times of sale, and even secured the carrying trade in their own hands. The sale of English sheep abroad, either for breeding or for shearing, was also forbidden under very heavy penalties. All these vexatious formalities in getting his wool to Calais, and the rapacity of the merchants of the Staple, disgusted the English farmer. As early as 1258 Simon de Montfort urged that England ought to be a centre of manufacture, and not merely a source of raw material. Edward III, while with one hand consolidating the power of the monopolists who controlled the Staple, on the other hand stimulated the obvious remedy. He invited Flemish weavers to settle in this country. By the end of his reign the whirring sound of the looms might be heard all through Norfolk, Essex and Kent. From a country of farmers which exported wool, England was soon to be transformed into a country of manufacturers who exported cloth. The sale of wool at the Staple dwindled away, while Yorkshire tweeds and Cotswold broadcloths were winning the preference for price and quality in the most distant markets.