Russian serfs were agrarian peasants legally bound to the land owned by nobility and who were deprived of rights and forced to provide free labor.
The term serf, in the sense of an unfree peasant of tsarist Russia, meant an unfree person who, unlike a slave, historically could be sold only together with the land to which they were "attached". However, this stopped being a requirement by the 19th century, and serfs were practically indistinguishable from slaves. Contemporary legal documents, such as Russkaya Pravda (12th century onwards), dis... Wikipedia