What was the character of Chmielnitski's rise? It has started as a private conflict between him and a polish nobel, Aleksander Czapliński. But what was after? And what was the reason to fight when Chmielnitski ruled all the Ukraine?
Bogdan Khmelnytsky was arguably the "William Wallace" of the Ukraine. He not only took on the one noble, but the whole Polish noble "Establishment," to the point where even the King of Poland (a personal friend), wouldn't defend him.
So he basically started a war between his Cossacks and the Poles. He was initially successful but the Poles were unforgiving; they wanted his head and continued the war, which started to turn in their favor. This drove him and Ukraine into the arms of Russia, and helped set the stage for Poland's decline and Russia's rise.