Treaty of Oliva is established between Sweden and Poland.

The Treaty of Oliva was signed in 1660 and brought an end to a long period of conflict between Sweden and Poland, specifically the Polish–Swedish wars that had been part of the wider Northern Wars. The treaty was concluded at the Abbey of Oliwa, near Gda?sk, and also involved other powers like Brandenburg-Prussia and the Holy Roman Empire. It marked a significant turning point in Northern European politics by stabilizing relations after years of territorial disputes and military campaigns.

One of the key outcomes of the treaty was that Poland formally recognized Swedish control over Livonia, a region along the eastern Baltic Sea that had been fiercely contested. In return, Sweden agreed to relinquish its claims to the Polish crown, ending a dynastic rivalry that had fueled earlier conflicts. Additionally, Brandenburg-Prussia gained full sovereignty over the Duchy of Prussia, which had previously been held as a fief under the Polish crown. This shift contributed to the rise of Prussia as a significant regional power in the years that followed.

The Treaty of Oliva helped establish a more stable balance of power in the Baltic region, though tensions between these states did not disappear entirely. It confirmed Sweden’s position as a dominant Baltic power during the 17th century, while Poland’s influence in the region began to decline. In the broader context of European diplomacy, the treaty is often seen as part of the post-Peace of Westphalia order, where negotiated settlements and recognition of sovereignty became central to maintaining stability across the continent.