The Pereyaslav Agreement was a treaty signed in 1654 between the Cossack Hetmanate, led by Bohdan Khmelnytsky, and the Tsardom of Russia. This agreement aimed to establish a military alliance against the Polish-Lithuanian Commonwealth, which had been oppressing the Cossacks. The Cossacks sought protection and autonomy under Russian rule while maintaining their own governance. The agreement marked a significant shift in the political landscape of Eastern Europe. It laid the groundwork for the eventual incorporation of the Cossack territories into the Russian Empire. Over time, the terms of the agreement led to tensions and conflicts regarding autonomy and governance between the Cossacks and the Russian authorities.