 Complete the following phrase:  In 1618, the famous second defenestration of Prague provoked the Thirty Years War, a particularly harsh period for Prague and Bohemia. Ferdid II of Habsburg was deposed, and his place as King of Bohemia taken by Frederick V, Elector Palatine; however his army was crushed in the Battle of White Mountain 1620 not far from the city. Following this in 1621 was an execution of 27 Czech Protestant leaders involved in the uprising in Old Town Square and the exiling of many others. Prague was forcibly converted back to Roman Catholicism followed by the rest of Czech lands. The city suffered subsequently during the war under an attack by Electoral Saxony 1631 and during the 