First Partition of Poland

By the late 18th century, the Polish–Lithuanian Commonwealth had diminished from a European power to a state under heavy influence from the Russian Empire, which effectively controlled the election of Polish–Lithuanian monarchs. The Repnin Sejm of 1767–68 exemplified this influence, as it was presided over by the Russian ambassador.

The First Partition was driven by the rising power of the Russian Empire, which threatened both the Kingdom of Prussia and the Habsburg monarchy. Frederick the Great of Prussia orchestrated the partition to prevent Austria from engaging in war against Russia, as Austria was concerned about Russian victories in the Russo-Turkish War.

The partition agreement was signed on February 19, 1772, in Vienna, following a previous agreement in Saint Petersburg on February 6, 1772. In August of that year, troops from Russia, Prussia, and Austria entered the Commonwealth to occupy the agreed-upon territories.

The partition resulted in the loss of approximately 211,000 square kilometres (30% of the Commonwealth's territory) and affected over four million people. Prussia gained significant territories, including parts of Royal Prussia and northern Greater Poland, while Austria acquired regions in Little Poland and Galicia. Russia took control of the northeastern territories, including parts of modern Belarus and Livonia.

Following the partition, King Stanisław August Poniatowski sought assistance from Western Europe but received little support. The partitioning powers compelled the Sejm to approve their actions through military pressure, leading to significant political and social upheaval within the Commonwealth, including in Ukraine, where the effects of the partition were felt deeply.