Between what two centuries were the Szlachta pirveleges, which formed the cornerstone of the Polish political system, granted?
Szlachta privileges The privileges of the "szlachta" (Poland's nobility) formed a cornerstone of "Golden Liberty" in the Kingdom of Poland and, later, in the Polish-Lithuanian Commonwealth. Most of the privileges were granted between the late 14th and early 16th centuries. By the end of that period, the "szlachta" had succeeded in garnering numerous privileges, empowering themselves and limiting the powers of the monarch to an extent unprecedented elsewhere in Europe at the time.
Treaty of Bromberg The Treaty of Bromberg (German: "Vertrag von Bromberg" , Latin: Pacta Bydgostensia) or Treaty of Bydgoszcz was a treaty between John II Casimir of Poland and Elector Frederick William of Brandenburg-Prussia, ratified at Bromberg (Bydgoszcz) on 6 November 1657. The treaty consisted of several agreements, including the Treaty of Wehlau signed on 19 September 1657 by the Brandenburg-Prussian and Polish-Lithuanian envoys in Wehlau (Welawa, now Znamensk). Thus, the treaty of Bromberg is sometimes referred to as treaty of Wehlau-Bromberg or Treaty of Wehlau and Bromberg (Polish: "traktat welawsko-bydgoski" ).