Dietine (soimyk; Polish: sejmik). Agency of territorial self-government by the nobility in Poland from the late 14th century, and local assembly of the Lithuanian and Ruthenian nobility in the Grand Duchy of Lithuania from 1564. Dietines convened in each county at first irregularly, but during the 16th century they became a legally recognized institution with a definite sphere of competence. The Lithuanian Statute of 1566 provided that four weeks before the convening of the Great Diet, the nobility (shliakhta) in every court district (sudovyi povit) (see Court system) should meet to discuss national and local affairs and needs, to elect two deputies to the Great Diet, and to instruct them. The dietines also chose four candidates for each of the offices of judge, assistant judge, and secretary of the provincial land court (zemskyi sud), from whom the grand duke appointed the three court officials. They also convened to receive the diet deputies' reports and to confer during an interregnum. In the 17th and 18th century the administrative role of the dietines increased with the decline of the central Polish government.
[This article originally appeared in the Encyclopedia of Ukraine, vol. 1 (1984).]