Reciprocal Guarantee of Two Nations

[4] In the preamble of this guarantee the dualistic form of the state was confirmed and it had equal status to the Union of Lublin (1569).

The document specified the nature of the Polish–Lithuanian union and affirmed "the unity and indivisibility", within a single state, of the Crown of the Kingdom of Poland and the Grand Duchy of Lithuania.

[4] The document was to be an integral part of the pacta conventa and thus binding on King Stanisław August Poniatowski and all subsequent monarchs of the Polish-Lithuanian state.

It specified that they shared a common government, military and treasury, but Lithuanian tax revenues were to be spent only within the Grand Duchy of Lithuania.

In the view of historians Stanisław Kutrzeba, Oskar Halecki and Bogusław Leśnodorski, the legislation adopted by the Four-Year Sejm, including the Mutual Pledge of the Two Nations, replaced the erstwhile union of the Crown of the Kingdom of Poland and the Grand Duchy of Lithuania, which had existed since the Union of Lublin (1569), with a unitary Polish Commonwealth, or Polish Republic.