Feudalism was a combination of legal and military customs in medieval Europe that flourished between the 9th and 15th centuries. Broadly defined, it was a way of structuring society around relationships derived from the holding of land in exchange for service or labour.
Although derived from the Latin word feodum or feudum (fief), then in use, the term feudalism and the system it describes were not conceived of as a formal political system by the people living in the Middle Ages. In its classic definition, by François-Louis Ganshof (1944),feudalism describes a set of reciprocal legal and military obligations among the warrior nobility, revolving around the three key concepts of lords, vassals and fiefs.
A broader definition of feudalism, as described by Marc Bloch (1939), includes not only the obligations of the warrior nobility but those of all three estates of the realm: the nobility, the clergy, and the peasantry bound by manorialism; this is sometimes referred to as a "feudal society". Since the publication of Elizabeth A. R. Brown's "The Tyranny of a Construct" (1974) and Susan Reynolds's Fiefs and Vassals (1994), there has been ongoing inconclusive discussion among medieval historians as to whether feudalism is a useful construct for understanding medieval society.
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.
Feudalism in 12th century 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 of 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.