With respect to the fighting class, it is characteristic of the Norman habit of order and organization that the military service of the nobles was early defined with more system and exactness in Normandy than in the neighboring countries of northern France. We have already seen that at a period well before 1066 the amount of service due from the great lords to the duke had been fixed in rough units of five or multiples of five, and these again subdivided among their vassals and attached to specific pieces of land which were hence called knights’ fees, an arrangement which the Normans carried to England and probably to Sicily as well. By 1172, when a comprehensive list was first drawn up, subinfeudation had produced about 1500 knights’ fees in Normandy, the largest holders being the bishop of Bayeux and the earl of Leicester with 120, the count of Ponthieu with 111, and Earl Giffard with 103. From these the class of fully armed knights reached down to the holders of small fractions of a knight’s fee, all however serving with the full armor which in course of time came to mark them off as nobles from the vavassors, or free soldiers, whose equipment was less complete and whose service tended to take the form of castle guard and similar duties. Quite early also custom had defined other characteristic features of the feudal service in Normandy, such as the period of forty days, the limitation of the obligation to the frontiers of the duchy, and the incidents of wardship and marriage, deductions from feudal principles which were here carried to their logical conclusions.