A tool extends human ability, either literally, as with the familiar hand implements of hammer, saw, and spade, or figuratively, as embodied in human organizations and institutions. All are means to the realization of individual and societal goals by overcoming the limitations of the individual. In the medieval European context, business made use of a vast array of tools. Some, like looms and spinning wheels, were essential to industrial processes; others, like accounting and credit instruments, proved invaluable to the solution of business problems; still others, like the company branch networks and guilds, provided superior organization. But all medieval business tools were shaped by the twin realities of opportunity and constraint and in particular by the need to mitigate constraints on the opportunities to trade. For it was exchange in all its forms that was both the goal and the lifeblood of medieval business enterprise.

What constrained trade? We have seen that medieval business developed in the narrow space between dominant lordship and peasant-based agriculture and that, as the junior partner, business had to accommodate itself to the devices and desires of the others. Senior partners, ofcourse, were the lords, both secular and ecclesiastical, who sought to fulfill divinely ordained roles as fighters or worshipers with scant regard for the pursuit of wealth as an end in itself. And though the lords created a great deal of wealth (largely through the efforts of their peasants), they were often indifferent to the economic effects of their actions.