At the heart of the storyline backplot and that of Flint's Eastern European thread is the Chmielnicki Rebellion, refers to a rebellion or war of liberation in the Polish–Lithuanian Commonwealth (present-day Ukraine), which raged from 1648–1654 and involved massive anti-semitic pogroms. Many of the Jews targeted had fled central and western Europe because the plague years in the 14th century had inspired pogroms, as did the spread of Lutheranism which was at the heart of the Thirty Years' War.