Revival of trade and commerce

The Romans had established a system of roads, water routes (via river and the open sea) and trading towns that provided ready markets and means of transportaitons for surplus or specialized goods. It was, for example, easier to manufacture cloth and metal good near the source of raw material (sheep or ore, respectively) than it was to ship raw materials overland or let every locality depend on their own resources. The German invasions upset this trading system and also destroyed the merchant forturnes that supplied the capital to finance this trade. From the 7th century --the nadir of civilization in Western Europe-- onwards, this trade began to rebuild itself. Central governments became more powerful and were able to provide a secure environment for trade. The cities, and their merchants, began growing again. There were now large sums of money available for merchants to buy quantities of trade goods and pay for their shipment to other areas. Local merchants now had sufficient captiral to make the annual slaughtering of excess (those that could not be fed through the winter) farm animals. Previously, the farmers had to either eat the meat of the slaughtered animals or, if sufficient salt and labor were available, preserve it. This approach led to waste, and there were fewer animals for breeding the following Spring. If merchants had the financial resources, they could buy sufficient fodder in the Fall, and then buy many animals cheaply and feed them over the Winter. These animals would be much more valuable in the Spring when they were re-sold. This bit of commerce made agriculture much more efficient, but you had to have sharp merchants with access to a lot of money to make it work.