Fiefs division could occur in a unlimited fashion, known as subinfeudation. This tended to weakening the unifying strength of the fief system due to exaggerated distributed power structure and reduced efficiency in the fuedal system.
The simplest form of a fief consisted as a self-sufficient estate.
Fiefs, typically 1000 to 2000+ acres, consisted of housing structures, barns, and gardens. There usually was a hall (not necessarily a manor), religious structures (commonly a church), a mill, a winery, and / or an oil press on the fief. The fief commonly had arable land, meadows, pastures (the commons), fishponds, and forests. Fiefs that possessed cultivated arable land were divided into three large fields and farmed by the three-field system of agriculture. One field was devoted to winter crops, another to summer crops, and a third lying fallow each year. The land was worked by peasants (known as serfs). Generally, rights of cultivation on the fief were heritable among the serfs
The vassal knight occupied the lord's fortified dwelling known as the manor house (if there was such a structure existing). Larger-than-common fiefs were in the hands of a vassals-in-chief. Although a fief was usually a piece of land, it could also take the form of money or food called a Knight's Fee.