The Polish-Lithuanian Commonwealth (1569-1795) was once the largest country in Europe--a multicultural republic that was home to Belarusians, Germans, Jews, Lithuanians, Poles, Ruthenians, Tatars, Ukrainians, and other ethnic and religious groups. Although long since dissolved, the Commonwealth remains a rich resource for mythmakingin its descendent modern-day states, but also a source of contention between those with different understandings of its...