Folwark (Belarusian: фальварак, Falvarak; German: Vorwerk; Lithuanian: Palivarkas) is a Polish word for a primarily serfdom-based farm and agricultural enterprise (a type of latifundium), often very large. Folwarks were operated in the Crown of Poland from the 14th century and in the Grand Duchy of Lithuania since the 15th century, from the second half of the 16th century in the joint Polish-Lithuanian Commonwealth, and survived after the partitions of the Commonwealth in the Russian Empire until the early 20th century. The purpose of folwarks was to produce surplus produce for export. The first folwarks were created on church- and monastery-owned grounds. Later they were adopted by both the nobility (szlachta) and rich peasants (singular: sołtys), but the sołtys positions were eventually taken over by the szlachta.
The term "folwark" came into the Polish language in the 14th century from the German "Vorwerk", originally the fortified advanced work of a castle, later an outlying manor house that managed a farm estate. The English translation would be grange, the historical meaning of which is "an outlying farm with tithe barns belonging to a monastery or feudal lord".
Creation of the folwarks was boosted by growing demand for grain and the profitability of its export, both to Western Europe and inside the Polish-Lithuanian Commonwealth. This led to the exploitation of serfdom, when land owners discovered that instead of money-based rent and taxes it was more profitable to force the peasantry to work on folwarks. Folwark-based grain export was an important part of the economy of the Polish-Lithuanian Commonwealth.
Folwarks were primarily an early modern, post-feudal rural formation. They originated as land belonging to a feudal lord (early on a knight) and not rented out to peasants but worked by his own hired labor or servants. The peasants toiled on the lots they rented from the lord, but in addition were obliged to provide complimentary labor for the lord on his folwark, originally a few days per year. From the 16th century, the amount of this mandatory free labor was radically increased and szlachta sponsored legislation imposed rigid conditions on the peasants, such as the prohibition on worker's right to leave a village and seek a new lord. The originally free peasants became serfs, and serfs then fell into a condition of extreme dependency and exploitation, known in Poland as wtórne poddaństwo [secondary serfdom]. Their lords in turn had become dependent on such slave labor, which kept the folwark economy going and "competitive" on the European grain markets.
In Poland serfdom was regulated (and increased) by the Privilege of Piotrków (1388) and the Privilege of Toruń (1520) (statutory privileges granted by kings to szlachta). With the fall of prices of agricultural goods at the end of the 17th century, the folwark economy was in crisis, and the szlachta's attempts to increase production by increasing the size of their folwarks (usually by appropriating peasant lands) and demanding more labour (usually by increasing the peasant workload) only compounded the economic crisis and further worsened the fate of the peasants, who had been, until then, no poorer than their average counterparts in Western Europe.
In Lithuania serfdom was fully established during the Wallach reform in the middle of the 16th century.
Until the end of the 18th century folwarks remained the basis for szlachta economic and political power. After the abolition of serfdom in Poland, folwarks used paid labor.
Folwarks were abolished by the People's Republic of Poland with the Polish Committee of National Liberation decree of 6 September 1944, concerned with agricultural reform. After the end of Second World War folwarks were nationalised, resulting in PGRs – state-owned collective rural enterprises (Państwowe Gospodarstwo Rolne) or partitioned, usually with little or no compensation to their owners.
- Gazeta Wyborcza newspaper wyborcza.pl 2012-08-22, Arkadiusz Pacholski, Jak Polak zhańbił Polaka, czyli niewolnictwo po polsku  [How a Pole shamed a Pole, or slavery in Polish]
- http://www.historycy.org portal, 2012-07-17, Przemysław Wielgosz, Pięćset lat kacetu. Ojczyzna-pańszczyzna  [Five hundred years of concentration camp. Fatherland-lord's land]