The 17th century did not seem to bring any relief to the religious conflicts that had started in Europe after the Reformation. This particular war started in 1618, a group of Bohemian nobles threw two Catholic governors out of a window in Prague Castle. This act, now known as Defenestration, was the beginning of this long war.
As evident, the conflict was between the Protestant noblemen of Bohemia (now Czech Republic) and their Catholic rulers (the Roman emperors). After the Defenestration, Bohemia’s noblemen chose Protestant Frederick of Bohemia as their king. The real battle began when in 1619, Ferdinand II became the new Roman emperor and he sent his troupes to attack Bohemia.
After the battle, Catholicism prevailed for a while. In around 1621, Spain also joined the war from Romans’ side and attacked the Protestant Dutch. In 1625, England and Denmark joined the war in support of the Dutch. France, which had suppressed Protestants in their own country, joined Protestant states in 1635, just to defeat Spain. Now, the war turned a different turn and French army dominated. But it was only in 1659 that the war would finally come to an end, and would leave the France as the most powerful country in Europe.