Social norms pervade all areas of life. They regulate which forms of human action are allowed and which are considered forbidden and are punishable by social, financial or other penalties for violations. Using the example of the land market in eastern Prussia, the study shows how at the end of the 19th century the nation was anchored as a point of reference for economic activity. Advocates of both the German and the Polish nation imposed the duty on their compatriots not to sell their property to members of the other nation - if they violated this rule, they were denigrated as traitors. Landowners, on the other hand, tried to thread lucrative deals without being penalized for choosing the buyer. Although both German and Polish landowners refused to support the Prussian state for its settlement policy, the latter managed to gain massive influence over property rights in the eastern provinces.