The legumes restored fertility to the soil and added protein to the peasants' diet. The new method allowed peasants to plant two thirds of their land, rather than half. In addition, lords who wanted to boost the incomes of their manors had peasants clear forests, drain swamps, and reclaim wasteland for farming and grazing.
All these improvements allowed farmers to produce more food. With more food available, the population began to grow. Between about 1000 and 1300, the population of Europe almost tripled.
Why did agricultural production improve?
Europe's growing population needed goods that were not available on the manor. Peasants needed iron for farm tools. Wealthy nobles wanted fine wool, furs, and spices from distant lands. As foreign invasions and feudal warfare declined, traders reappeared, crisscrossing Europe to meet the growing demand for goods.
Enterprising traders formed merchant companies that traveled in armed caravans for safety. They followed regular trade routes, many of which had hardly been used for centuries. Along these routes, merchants exchanged local goods for those from remote markets in the Middle East and from still farther east in Asia.
In Constantinople, merchants bought Chinese silks, Byzantine gold jewelry, and Asian spices. They shipped these goods by sea to Venice, where traders loaded their wares onto pack mules and headed north to Flanders. There, other traders bought the goods at trade fairs and sent them to England and lands along the Baltic Sea. Northern Europeans paid for these goods with products such as honey, furs, cloth, tin, and lead.
Annual trade fairs were an early sign of economic revival. Traders from all over Europe met at fairs near navigable rivers or where trade routes met. Trading lasted for weeks. The fairs became elaborate events with entertainments as well as goods.
The trade fairs gradually declined, in part because of competition from the Hanseatic League, an association of towns in northern Germany that banded together to protect their trading interests. The league used its shipping fleets to clear the northern seas of pirates and boost trade in furs, timbers, and fish.
Active trade routes brought in new ideas as well as new goods.