Examples of feudalism are helpful to fully understand feudalism and feudal society. Feudalism was practiced in many different ways, depending on location and time period, thus a high-level encompassing conceptual definition does not always provide a reader with the intimate understanding that detailed historical examples provide. Western European Feudalism 12th century England Feudalism in 12th century Norman England was among the better structured and established in Europe at the time. However, it could be structurally complex, which is illustrated by the example of the feudal barony of Stafford as described in a survey of knight's fees made in 1166 and recorded in The Black Book of the Exchequer. This was a roll of parchment or several such, recording the quantity and tenant of each knight's fee held in capite. It was a record commissioned by the Treasury as the knight's fee was the primary basis for assessing certain types of taxation, for example, feudalism is the exchange of land for military service, thus everything was based on what was called the knight's fee, which is a fiefdom or estate of land. A feudal barony contained several knight's fees, for example the baron Robert de Stafford held a barony containing 60 knight's fees. Often lords were not so much lords presiding over great estates, but managers of a network of tenants and sub-leases. Stafford tenants were themselves lords of the manors they held from him, which is altogether different from their being barons. Henry d'Oilly, who held 3 fees from Robert de Stafford, also held, as a tenant-in-chief, over 30 fees elsewhere that had been granted to him directly by the king. Thus while Henry was the vassal of his overlord Robert, Henry was himself a lord of his own manors held in capite and sub-enfeoffed many of his manors which he did not keep in demesne, that is to say under his own management using simple employees. It would also have been possible and not uncommon for a situation where Robert of Stafford was a vassal of Henry elsewhere, creating the condition of mutual lordship/vassalage between the two. These complex relationships invariably created loyalty problems through conflicts of interests. To resolve this the concept of a liege lord existed, which meant that the vassal was loyal to his liege lord above all others, except the king himself, no matter what. However, even this sometimes broke down when a vassal would