Complex sentence: The Crimean Khanate was undoubtedly one of the strongest powers in Eastern Europe; the Polish-Lithuanian Commonwealth and Russia suffered a series of Tatar invasions, the goal of which was to loot, pillage and capture slaves into jasyr.
Split into simpler sentences: The Crimean Khanate was undoubtedly one of the strongest powers in Eastern Europe. The Polish-Lithuanian Commonwealth and Russia suffered a series of Tatar invasions, the goal of which was to loot, pillage, and capture slaves into jasyr.