structural:expansion
First Partition

In February 1772, the agreement of partition was signed in Vienna. Early in August, Russian, Prussian and Austrian troops occupied the provinces agreed upon among themselves. However, fighting continued as Bar confederation troops and French volunteers refused to lay down their arms (most notably, in Tyniec, Częstochowa and Kraków). On August 5, 1772, the occupation manifesto was issued, to the dismay of the weak and exhausted Polish state; the partition treaty was ratified by its signatories on September 22, 1772.

Frederick II of Prussia was elated with his success; Prussia took most of Royal Prussia (except Gdańsk) that stood between its possessions in Prussia and the Margraviate of Brandenburg, as well as Ermland (Warmia), northern areas of Greater Poland along the Noteć River (the Netze District), and parts of Kuyavia (but not the city of Toruń).

Despite token criticism of the partition from Empress Maria Theresa, Austrian statesman Wenzel Anton, Prince of Kaunitz-Rietberg, was proud of wresting as large a share as he did, with the rich salt mines of Bochnia and Wieliczka. To Austria fell Zator and Auschwitz (Oświęcim), part of Lesser Poland embracing parts of the counties of Kraków and Sandomir and the whole of Galicia, less the city of Kraków.

Empress Catherine II of Russia was also satisfied despite the loss of Galicia to the Habsburg monarchy. By this "diplomatic document" Russia gained Polish Livonia, and lands in eastern Belarus embracing the counties of Vitebsk, Polotsk and Mstislavl.

By this partition, the Polish–Lithuanian Commonwealth lost about 30% of its territory and half of its population (four million people), of which a large portion had not been ethnically Polish. By seizing northwestern Poland, Prussia instantly gained control over 80% of the Commonwealth's total foreign trade. Through levying enormous customs duties, Prussia accelerated the collapse of the Commonwealth.

After having occupied their respective territories, the three partitioning powers demanded that King Stanisław and the Sejm approve their action. When no help was forthcoming and the armies of the combined nations occupied Warsaw to compel by force of arms the calling of the assembly, the only alternative was passive submission to their will. The so-called Partition Sejm, with Russian military forces threatening the opposition, on September 18, 1773, signed the treaty of cession, renouncing all claims of the Commonwealth to the occupied territories.

In 1772, Jean-Jacques Rousseau was invited to present recommendations for a new constitution for the Polish–Lithuanian Commonwealth, resulting in the Considerations on the Government of Poland (1782), which was to be his last major political work.