Stanislaw August's process of renovation reaches its climax on May 3, 1791, when, after three years of intense debate, the "Four Years' Sejm" produces Europe's first written constitution.

Conceived in the liberal spirit of the contemporaneous document in the United States, the constitution recasts Poland-Lithuania as a hereditary monarchy and abolishes many of the eccentricities and antiquated features of the old system.

The new constitution abolishes the individual veto in parliament; provides a separation of powers among the legislative, executive, and judicial branches of government; and established "people's sovereignty" (for the noble and bourgeois classes).

Although never fully implemented, the Constitution of May 3 gains an honored position in the Polish political heritage; tradition marks the anniversary of its passage as the country's most important civic holiday.