Thus, the situation of ethnic composition previous to the century is known from the various separate sources: various records and inventories, descriptions and memoirs of contemporaries, language of the sermons used in the churches, registers of births and deaths; various state published documents: statutes, acts, decrees, prescriptions, declarations etc. The lists of peasants‘ pays for plots and grinding of flour was also demographic source. Lithuanian and German proportion of Piliakalnis (Dobrovolsk) in the middle of the 18th century was determined by O. Natau on the ground of these lists. The toponymy of Prussia and its changes is also a source for situation of Lithuanians.