The Thirty Years War which broke out in the year 1618 and which ended with the famous treaty of Westphalia in 1648 was the perfectly natural result of a century of ever increasing religious hatred. It was, as I have said, a terrible war. Everybody fought everybody else and the struggle ended only when all parties had been thoroughly exhausted and could fight no longer. In less than a generation it turned many parts of central Europe into a wilderness, where the hungry peasants fought for the carcass of a dead horse with the even hungrier wolf. Five-sixths of all the German towns and villages were destroyed. The Palatinate, in western Germany, was plundered twenty-eight times. And a population of eighteen million people was reduced to four million. The hostilities began almost as soon as Ferdinand II of the House of Habsburg had been elected Emperor. He was the product of a most careful Jesuit training and was a most obedient and devout son of the Church. The vow which he had made as a young man, that he would eradicate all sects and all heresies from his domains, Ferdinand kept to the best of his ability. Two days before his election, his chief opponent, Frederick, the Protestant Elector of the Palatinate and a son-in-law of James I of England, had been made King of Bohemia, in direct violation of Ferdinand's wishes. At once the Habsburg armies marched into Bohemia. The young king looked in vain for assistance against this formidable enemy. The Dutch Republic was willing to help, but, engaged in a desperate war of its own with the Spanish branch of the Habsburgs, it could do little. The Stuarts in England were more interested in strengthening their own absolute power at home than spending money and men upon a forlorn adventure in far away Bohemia. After a struggle of a few months, the Elector of the Palatinate was driven away and his domains were given to the Catholic house of Bavaria. This was the beginning of the great war. Then the Habsburg armies, under Tilly and Wallenstein, fought their way through the Protestant part of Germany until they had reached the shores of the Baltic. A Catholic neighbour meant serious danger to the Protestant king of Denmark. Christian IV tried to defend himself by attacking his enemies before they had become too strong for him. The Danish armies marched into Germany but were defeated. Wallenstein followed up his victory with such energy and violence that Denmark was forced to sue for peace. Only one town of the Baltic then remained in the hands of the Protestants. That was Stralsund.