THIRTY YEARS' WAR, so called be cause it lasted from 1618 to 1648, was at first a struggle between Protestants and Roman Catho lics, north Germany supporting the former, and southern Germany, with Austria at its head, the latter cause. It gave the Swedes an opportunity to extend their dominion south of the Baltic, it reduced the resources and weakened the power of Austria, and it gained for the northern states of Germany the breathing space needed to develop independent existence. Few wars, however, have been more calamitous in their general effect on the mass of the people and the happiness and progress of mankind. Apart from the horrors which attended the capture of Magdeburg, and other barbarous scenes of the struggle, it reduced the peasantry and most of the townspeople to abject misery; it may be said to have effaced for a time literature and art in Germany, and it magnified the system of petty principalities, since partly effaced as a result of the Napoleonic wars, but still a powerful obstacle in the way of complete Ger man progress.
On the one side were Austria, nearly all the Roman Catholic princes of Germany, and Spain; on the other side were, at different times, the Protestant powers and France. The occasion of this war is to be found in the fact that Ger many had been distracted ever since the Refor mation by the mutual jealousy of Roman Catholics, Lutherans and Calvinists, which led the Protestant princes to form the Evangelical Union in 1608, against which the Roman Catho lic League was formed the following year. Certain concessions had been made to the Protestants of Bohemia by the Emperor Ru dolph II (1609), but these were withdrawn by his successor Matthias in 1614, and four years afterward the Bohemian Protestants were in rebellion. Thus began the first part of the long war, the part that is known as the Bohemian War. The Protestant Bohemians were led by the Count of Thurn, and the Union sent an auxiliary corps into Bohemia, under the corn mand of the brave Ernest, count of Mansfeld. Their leaders drove the imperial troops from Bohemia, invaded the archduchy of Austria, and advanced to the gates of Vienna, but un favorable weather and want of resources com pelled the invaders to retreat. Soon after, Ferdinand, with the title of Ferdinand II, was chosen emperor (28 Aug. 1619). He had borne the title of king of Bohemia since the resig nation of his cousin Matthias in 1617. The Bohemians, knowing his hostility to Protestant ism, had already declared his title to the Bo hemian crown void, and offered it to the elector palatine, Frederick V, the head of the Prot estant Union, and husband of Elizabeth, &ugh• ter of James I of England. Frederick accepted
the crown, but he was ill fitted to cope with the difficulties before him, and the great victory of the troops of the League (8 Nov. 1620), under Maximilian of Bavaria, on the Weissenberg (White Mountain), near Prague, which was followed by the flight of the new king, put an end to the Bohemian rebellion, and crushed the Protestant cause in that quarter. Frederick was put under the ban of the empire, his territory was taken from him and bestowed on Maxi of Bavaria.
Ferdinand had now a favorable opportunity of concluding a peace on moderate terms. But his unsparing treatment of the conquered, and the reactionary proceedings against the Prot estants generally, all of whom had been expelled from Bohemia, at last roused the determined opposition of the Protestant princes, who sought and obtained foreign assistance. Aided by sup plies of money from England, and by a body of troops from Holland, Count Mansfeld, Chris tian of Brunswick, and the Margrave of Baden again took the field, and they were joined by Christian IV of Denmark. Mansfeld was de feated by the imperial general Wallenstein at Dessau (25 April 1626), and after a difficult march through Hungary to the lower Danube, died in Bosnia on 30 November in the same year. Meanwhile Christian of Brunswick had also died, and Christian of Denmark had been defeated by Tilly at Lutter am Barenberg (27 Aug. 1626) and compelled to withdraw to his __own territory. The allies of Denmark, the dukes of Mecklenburg, were now obliged to flee from their territories, which were taken possession by Wallenstein with the consent of the emperor. Holstein, Schleswig and Jutland also soon fell into the hands of the imperial troops. Pomerania and Brandenburg had de tachments forced upon them by Wallenstein. The power of the emperor extended to the Bal tic, and to secure this power an attempt was made to seize all the important towns on the coast. Straslund alone made serious resistance, and during a ten-weeks' siege, which was car ried on with furious energy (May to July 1628), it baffled all the attacks of Wallenstein, who was at last forced to retreat with great loss. This check thwarted the plans of Wallenstein, and led to a short interruption of the war. In the peace of Lubeck (12 May 1629) Christian of Denmark received hack all the territories belonging to him that had been occupied and devastated by the imperial troops, on the condi tion of promising to interfere no more in the affairs of Germany.