The Treaty of Oliva was signed on May 3, 1660, to end the conflict between the Polish-Lithuanian Commonwealth and the Swedish Empire. This treaty concluded the Second Northern War, which had caused significant territorial and political changes in the region. Under the terms of the treaty, Sweden retained control over parts of Livonia and Prussia, while the Commonwealth regained some territories. The agreement also established a framework for future relations between the two powers, promoting peace and stability in Eastern Europe for several years.