Since the tenth century, merchants and craftsmen have become very important. Particularly these as producers of new goods, increasingly needed for urban life and traders as distributors of such goods or merchandise. The flourishing of the great international trade, from the tenth century, both terrestrial and maritime, is a natural consequence of agricultural and livestock expansion.
From the tenth century the figure of the merchant and the bourgeois, who may coincide, take an important role in the organization of Western European society and its role will increase in the course of the next centuries.
Merchants can not develop their activities only in a particular place, if they wish to prosper, and are forced to associate to travel more safely and even to arm themselves. The transit of caravans of merchants requires an interior organization and necessity creates the head of the caravan.
Merchants who make long and heavy journeys, by land or by sea, with innumerable dangers, travel from one place to another with their servants and bundles, carrying products of low weight and high prices and, to defend themselves against thieves and murderers who lurk their passage, are armed and accompanied by people of arms.
From the tenth to the twelfth century local markets are multiplied and fairs are created around the important urban centers where, on the occasion of solemn festivities that usually carry the parties and the fun, with the consequent meeting of people of provenance and condition very diverse, merchants can find the opportunity to do good business. Here will appear the first money changers and bankers, ready to realize his business also changing some currencies for others to prices inferior to the one of its real value. The merchants themselves will become money changers too.
Monetary circulation, increasingly intense, will favor exchanges against the exchange of some goods by others. The knowledgeable merchant knows where there are enough goods to buy cheaper, and where they are lacking and want to sell more expensive, either by bartering or by paying cash and cash.
The merchant will know how to handle the weapons and protect themselves with them. The urban militias will not be formed by professionals of the arms, but by people who, having made artisan work or commerce their way of life, own weapons and know how to use them to protect their lives and their interests.
In the social order of the time, the merchants continue to constitute a minority, even within the order of the workers. It matters little that division and specialization have arisen in the world of work. Those who continue to dominate it remain the peasants and cattlemen, but the innovative force of the merchant and artisan bourgeoisie will emerge the germ that will undermine the essence and force of the feudal world and will shake its structures.