<P> 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 . </P> <P> 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 . </P> <P> A broader definition of feudalism, as described by Marc Bloch (1939), includes not only the obligations of the warrior nobility but also 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 . </P> <P> There is no commonly accepted modern definition of feudalism, at least among scholars . The adjective feudal was coined in the 17th century, and the noun feudalism, often used in a political and propaganda context, was not coined until the 19th century, from the French féodalité (feudality), itself an 18th - century creation . </P>

What are the four class levels in feudalism