Polish-Prussian alliance

The Polish–Lithuanian and Prussian alliance was a mutual defense alliance signed on 29 March 1790 in Warsaw between representatives of the Polish–Lithuanian Commonwealth and the Kingdom of Prussia. It was signed in the brief period when Prussia was seeking an ally against either Austria or Russia, and the Commonwealth was seeking guarantees that it would be able to carry out significant governmental reforms without foreign intervention.

From the beginning, the alliance was much more valuable to the Commonwealth than to Prussia. Soon after the treaty was signed, the international situation, and changes within the Commonwealth, made the treaty much less valuable to the Prussian side. Meanwhile, the Commonwealth embarked on a series of major internal reforms, seeing the alliance as a guarantee that it had the backing of a powerful neighbor in this process – where in fact Prussia felt those reforms were not in its best interest, and felt threatened by them. When Russia invaded the Commonwealth in May 1792, Prussia refused a request to honor the alliance and intervene, arguing that it was not consulted with regard to the 3rd May Constitution, which invalidated the alliance. A few months later, in 1793, Prussia aided Russia in the suppression of the Kościuszko Uprising.

The Polish–Lithuanian Commonwealth (also known as the Republic of Poland) had been a major European power since its formation in the late 16th century and was still one of the largest states on the European continent in the latter part of the 18th century. Over time, its state machinery had become increasingly dysfunctional. By the early 17th century, the magnates of Poland and Lithuania controlled the state—or rather, they managed to ensure that no reforms would be carried out that might weaken their privileged status (the so-called "Golden Freedoms"). Tentative reforms began in the late 18th century; however, any idea of reforming the Commonwealth was viewed with suspicion not only by its magnates but also by neighboring countries, which were content with the state of the Commonwealth's affairs and abhorred the thought of a resurgent and democratic power on their borders. With the Commonwealth Army only numbering around 16,000, it was easy for its neighbors to intervene directly: the Imperial Russian Army numbered 300,000; the Prussian Army and Imperial Austrian Army, 200,000. All of those powers had already annexed about a third of the Commonwealth territory and population (211,000 square kilometers (81,000 sq mi) and four to five million people) in the First Partition of Poland in 1772–1773.

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