One important cause of the revival of towns and trade beginning in about AD 1000 was Charlemagne's vision of a formally structured social order. The concept is dimly reflected in the Oaths of Strasbourg, wherein brothers Charles the Bald and Louis the German formally bind themselves to each other against their brother Lothar. The concept of "aid[ing] my brother just as one should" (Oaths 13), reinforced by Charles and Louis' pledge "each free man in our realms" to the service of each other for military purposes, hints at the system of vassalage loyalties whereby one person sells his service to his lord (Mersen 135). The Capitulary of Quierzy of 877 (135) enshrines the concept by binding the vassals' vassals and the heirs of vassals to loyalty to the lord.
Once the basic concept was enshrined, it was continually refined and increasingly became a matter of record. The survey of Neuillay dated 860 gives the lord an accounting of his slaves (and the slaves (dependents) of vassals), their duties, living space, taxes, and in general what amount to their job descriptions with respect to care and maintenance of the lord's lands (Neuillay 137). The AD 1050 document "Rights and Ranks of People" identifies cash and in-kind payments due to those bound to the manor, as well as their rights to private property and duties to the lord's lands (that document makes provision for holiday foods to the slaves).
All of these documents show protecting the position of the lord. But a more generalized system is emerging. By the time of the May Fair at Provins in 1164, Henry of Troyes is making regulations for what today would be called booth space and threatening fines and merchandise confiscation for violators (179). Gies and Gies note that trade fairs were kept alive at key ports where merchants from different places could deal with each other (108). It is noteworthy of the May Fair of 1164 that the money changers--undoubtedly Jews--have to stay in...