LTReikšminiai žodžiai: Lietuvos Metrika; Lietuvos Didžioji Kunigaikštystė (LDK; Grand Duchy of Lithuania; GDL); Šaltiniai, istoriniai; Lithuanian metrica; Historical sources.
ENThe oldest povet land court books are among the most important sources for the investigation of the court reform of 1564-1566 in the Grand Duchy. The paper surveys these books, their number and amount. It also deals with the history, the formation of the archival complex of court books and their fate in the historical cataclysms of the twentieth century. The present-day state of the extant 21 books of the earliest land court records is compared with the archival catalogues (and separately described books), compiled in the late nineteenth and early twentieth centuries. A conclusion is made that many former inventories do not reflect the contemporary situation, since the extant books are merely small fragments of the late sixteenth century court books. All of them are listed in a separate table. Nevertheless a supposition is made that the investigation of the oldest land court records covering the period between 1564 and 1588 could shed new light on the practical realization of the reform of law courts in the second half of the sixteenth century. [From the publication]