In 1454 King Casimir IV granted the Nieszawa Statutes (Polish: "statuty cerkwicko-nieszawskie"), clarifying the legal basis of voivodship sejmiks (local parliaments). The king could promulgate new laws, raise taxes, or call for a levée en masse (pospolite ruszenie) only with the consent of the sejmiks, and the nobility were protected from judicial abuses. The Nieszawa Statutes also curbed the power of the <answer>magnates</answer>, as the Sejm (national parliament) received the right to elect many officials, including judges, voivods and castellans. These privileges were demanded by the szlachta as a compensation for their participation in the Thirteen Years' War.
Whos power was curbed?
magnates