Pacta conventa

Pacta conventa (Latin for "articles of agreement") was a contractual agreement entered into between the "Polish nation" (i.e., the szlachta (nobility) of the Polish–Lithuanian Commonwealth) and a newly elected king upon his "free election" (wolna elekcja) to the throne from 1573 to 1764.

[3] The pacta conventa affirmed the king-elect's pledge to respect the laws of the Commonwealth and specified policies to be enacted in foreign policy, state finances, the armed forces, public works and other areas.

[2] An example of the various concrete undertakings found in a king-elect's pacta conventa is King Władysław IV Vasa's pledge to create a Polish–Lithuanian Commonwealth Navy for the Baltic Sea.

Each King's pacta conventa was different based on the specific policies he had promised in order to be elected, making it somewhat similar to a modern political platform or manifesto.

Together, those two documents spelled out most of the critical details of the Commonwealth political system.