THIRTY YEARS' WAR (1618 to 1648), a war in Germany, at first a strug gle between Roman Catholics and Prot estants. Subsequently it lost its relig. ious character and became a struggle for political ascendancy in Europe. On the one side were Austria, nearly all the Roman Catholic princes of Germany, and Spain; on the other side were, at dif ferent times, the Protestant powers and France. The occasion of this war was found in the fact that Germany had been distracted ever since the Reformation by the mutual jealousy of Catholics, Luther ans, and Calvinists. Certain conces sions had been made to the Protestants of Bohemia by Rudolph II. (1609), but these were withdrawn by his successor Matthias in 1614, and four years after ward the Bohemian Protestants were in rebellion. Count Thurn at the head of the insurgents repeatedly routed the im perial troops, compelling them to retire from Bohemia, and (1619) invaded the archduchy of Austria. Matthias having died in 1619, he was succeeded by Fer dinand II., who was a rigid Catholic, but the Protestants elected as their king Frederick, Elector Palatine, who was a Protestant. Efforts at mediation having failed, the Catholic forces of Germany marched against Frederick, who, with an army of Bohemians, Moravian, and Hungarians, kept the field till Nov. 8, 1620, when he was totally routed at Weis senberg, near Prague, by Duke Maximil ian of Bavaria. The Protestant cause was now crushed in Bohemia, and the people of that province suffered cruel persecution. The dominions of Freder ick, the Palatinate of the Rhine includ ed, were now conquered, the latter being occupied by Count Tilly, assisted by the Spaniards under Spinola. At the Diet of Ratisbon (March, 1623) Frederick was deprived of his territories, Duke Maximilian receiving the Palatinate.
Ferdinand, whose succession to the throne of Bohemia was thus secured, had now a favorable opportunity of conclud ing a peace, but his continued intolerance toward the Protestants caused them to seek foreign assistance, and a new period of war began. Christian IV. of Den mark, induced partly by religious zeal and partly by the hope of an acquisition of territory, came to the aid of his Ger man coreligionists (1624), and being joined by Mansfeld and Christian of Brunswick, advanced into Lower Sax ony. There they were met by Wallen stein, Duke of Friedland, who in 1626 defeated Mansfeld at Dessau, while Til ly was also successful in driving Chris tian back to Denmark. In the peace of
Liibeck which followed (May, 1629) Christian of Denmark received back all his occupied territory, and undertook not to meddle again in German affairs. After this second success, Ferdinand again roused his people by an edict which re quired restitution to the Roman Catho lic Church of all church lands and prop erty acquired by them since 1552.
To the assistance of the Protestants of Germany, in these circumstances, came Gustavus Adolphus, King of Sweden, who landed (1630) with a small army on the coast of Pomerania. Joined by numerous volunteers, and aided by French money, he advanced, and routed Tilly at Brei tenfeld (or the battle of Leipsic, Sep tember, 1631), victoriously traversed the Main and the Rhine valleys, defeated Tilly again near the confluence of the Lech and the Danube (April, 1632), and entered Munich. Meanwhile the emper or sought the aid of Wallenstein, by whose ability and energy Gustavus was obliged to retire to Saxony, where he gained the great victory of Liitzen (No vember, 1632), but was himself mortally wounded in the battle. The war was now carried on by the Swedes under the chan cellor Oxenstierna, till the rout of the Swedish forces at Nordlingen (Septem ber, 1634) again gave to the emperor the preponderating power in Germany. The Elector of Saxony, who had been an ally of Gustavus, now made peace at Prague (May, 1635), and within a few months the treaty was accepted by many of the German princes.
The Swedes, however, thought it to their interest to continue the war, while France resolved to take a more active part in the conflict. Thus the last stage of the war was a contest of France and Sweden against Austria, in which the Swedish generals gained various suc cesses over the imperial forces, while the French armies fought with varied for tunes in West Germany and on the Rhine. Meanwhile the emperor had died (1637), and had been succeeded by his son, Fer dinand III. The struggle still continued till in 1646, the united armies of the French under the great generals Turenne and Conde, and the Swedes advanced through Suabia and Bavaria. The com bined forces of Sweden and France were then about to advance on Austria, when the news reached the armies that the peace of Westphalia (1648) was con cluded, and that the long struggle was ended.