Thirty Years' War, a religious and political conflict which involved the German empire, and with it the principal states of Europe, from 1618 to 1648. The causes which led to this struggle reach back to the early part of the 16th century, when the reformation divided Germany into two hostile religious parties. Protestantism, nearly crushed in the Avar of the Smalcald league, rose triumphant under Maurice of Saxony, and with the peace of Augsburg (1555) Charles V. beheld the chief aim of his policy for ever frustrated. By the terms of this peace, which extended to those Protestants only who had embraced the confession of Augsburg, the right was secured to each state of prescribing the form of worship within its limits, and to all subjects, Lutheran or Catholic, the privilege of emigrating from the states where their creed was prohibited. The Protestants were to retain the ecclesiastical possessions which they had appropriated previous to the peace of Passau in 1552. But though the basis of a definite settlement was established, two important points remained on which no agreement could be reached.

The Catholic party, to guard against the danger that would accrue to the church in the future appropriation of her prelacies by the Protestants, introduced an article, known as the ecclesiastical reservation, by which all prelates who should henceforth abjure Catholicism were to forfeit their benefices. This article was inserted against the protest of the Lutheran members of the diet. The other point related to Protestant subjects in the ecclesiastical states, for whom the Protestant members sought to secure the right of worship in such territories. The Catholics refused to admit such an article, and they could only obtain instead a personal declaration to the same effect from the emperor's brother Ferdinand, who presided at the diet of Augsburg. The exclusion of the Calvinists proved another source of contention. Under the rule of Ferdinand I. (1556-'64) and his son, the mild Maximilian II. (1564-'76), a general tranquillity was maintained, while the balance was fast turning toward the side of the Protestants, who in the Austrian territories began to tyrannize over the Catholics. The bigoted Rudolph II. (1576-1612), swayed by the Jesuits and the court of Spain, resolved to repress Protestantism, and in his immediate dominions proceeded to restrict, and finally even to abolish the Protestant worship.

Religious disputes again distracted Germany. The enmity between Lutherans and Calvinists equalled their mutual hate for the Catholics. The aulic council, whose decisions were inspired by the imperial court, usurped an unlawful jurisdiction in the empire. In Aix-la-Chapelle the Protestants established their worship in spite of the Catholics (1580), and at first beat back the troops sent to execute the imperial ban. About the same time an opportunity was presented of enforcing the ecclesiastical reservation. Gebhard, archbishop of Cologne, abjured his faith to marry a Calvinist lady, but determined not to renounce his see. He was accordingly placed under the ban of the empire, and a war ensued, which ended in his defeat and expulsion in 1584. A violent contest followed for the see of Strasburg. In 1607 the Protestant imperial city of Donauworth, whose inhabitants an abbot had provoked to acts of violence by processions, prohibited within the town, was deprived of its liberties, in open violation of the peace of religion.

Alarmed for their safety, the Protestant princes, in May, 1608, formed at Auhauscn in Franco-nia an offensive and defensive league styled the "Evangelical Union." It soon comprised the Palatinate, Neuburg, Baden, Wurtemberg, Brandenburg, Strasburg, Nuremberg, and other states of the empire. Frederick IV., elector palatine, a Calvinist, was placed at its head, though its most active member was Christian of Anhalt. The Lutheran elector of Saxony, however, declined to join the union. On their side the Catholic states, independently of Austria, established the league (July, 1609), with Maximilian, duke of Bavaria, at their head. In the mean while the Protestants of Hungary and Austria had risen against Rudolph and recovered their rights (see Rudolph II., and Matthias); and thus encouraged, their brethren in Bohemia, in July, 1609, wrung the Majestatsbrief from the emperor. Amid these disorders the heirless duke of Julich died (March, 1609), leaving a host of claimants to his dominions, which were at once jointly seized by Brandenburg and Neuburg. Rudolph ordered a levy of troops to enforce their sequestration. The Protestant princes flew to arms, and invoked the aid of France, the Netherlands, and other powers.

Henry IV. of France now hoped to execute his design of humbling the house of Hapsburg, and was preparing to invade Germany when the dagger of Ravaillac terminated his career (May 14, 1610). Hostilities ceased, but under the emperor Matthias, who succeeded in 1612, the unsettled claims of Julich again led to war, and Dutch and Spaniards, called in by Brandenburg and Neuburg respectively, occupied the disputed lands. Matthias, being without heirs, was induced to put forward as his successor his cousin Ferdinand of the Styrian line, whose bigotry and rigor alarmed the Protestants. Ferdinand was nevertheless crowned in Bohemia in 1617 and in Hungary in 1618. But already in Bohemia an event had occurred which precipitated the thirty years' war. The Protestant inhabitants of Klostergraben and Braunau had erected new churches against the prohibition of the archbishop of Prague and the abbot of Braunau, lords of the two places, who enforced their authority by seizing the buildings. Protestants and Catholics appealed to a somewhat obscurely worded clause in the Majestatsbreff, which the former contended gave the right of building new churches to the Protestants of the towns in general, while the latter maintained that it extended only to the states and royal towns.

The court supported the Catholics, and refused all redress. The storm now burst. On May 23, 1618, an assemblage of Protestants, led by Count Thurn, entered the palace at Prague, and seizing Sla-vata and Martinitz, the most odious members of the council of regency appointed by the crown, hurled them together with their secretary from a lofty window. They escaped as if by a miracle, Thurn and his associates organized a general rising, and evoked the assistance of the union and of Bethlen Gabor of Transylvania. In a short time nearly all Bohemia was in their hands. They were joined by the Silesians, and by Mansfeld with 4,000 men raised by the union. Matthias was forsaken by the empire, and the troops of Spain sent to his aid, under Bucquoy and Dampierre, were unable to check the insurrection, which spread into Upper Austria and Moravia. In the midst of this crisis Matthias died (March, 1619), and Ferdinand, abandoned by his subjects, was soon shut up in Vienna by the victorious Thurn. His firmness and timely succor from Dampierre saved his sinking throne.

Thurn withdrew, and Ferdinand, hastening to Frankfort, was elected emperor (August, 1619). The Bohemians, who had declared their throne vacant, offered it to the young elector palatine Frederick V., son-in-law of James I. of England, and he was crowned in Prague. Bethlen Gabor overran Hungary, and Vienna was again threatened, but again saved. The emperor now prepared to conquer Frederick by means of the duke of Bavaria, who was to be indemnified for his services. Maximilian assembled the forces of the league, awed the union into inaction, and quickly subdued Upper Austria. John George, the elector of Saxony, though a Protestant, took up arms against Frederick, and overran Lusatia, and the Spanish general Spinola invaded the Lower Palatinate, while Maximilian joined Bucquoy in Bohemia. The battle of the White mountain, before the walls of Prague, Nov. 8, 1620, drove Frederick from his throne, and left Bohemia to the vengeance of the emperor. Executions and confiscations followed. The Protestant worship was abolished, the kingdom given over to the Jesuits, and the Majestatsbrief cut into pieces.

The electoral dignity, forfeited by Frederick, and the Upper Palatinate, were eventually transferred to Maximilian. The battle of Prague was followed by the dissolution of the Protestant union, but the intrepid Mansfeld, who had not shared in the defeat, determined to retain his army. He marched from Bohemia to Alsace, and struggled with Tilly, the general of Maximilian and the league. George Frederick, margrave of Baden-Durlach, and Christian of Brunswick, a lawless adventurer like Mansfeld, who made war support war, took up arms for Frederick. Tilly crushed the margrave at Wimpfen on the Neckar, and routed Christian at Hochst (1622). Christian and Mansfeld passed into the Netherlands, but soon renewed the contest with Tilly, who finally drove them from the field. Bethlen Gabor, who had broken the peace of Nikolsburg and ponetrated into Moravia, made a truce with the emperor in 1624. The Catholic party was triumphant, but the persecutions and the excesses which now ensued rekindled the flames of war. The states of Lower Saxony rose in 1625, and united with Christian IV. of Denmark, who took the lead in the struggle. England sent subsidies, Holland aided with troops, and Christian of Brunswick and Mansfeld reappeared in the field.

Hitherto it was not with the forces of Austria but with thoso of the league and Spain that Ferdinand had carried on the contest. Wallenstein now came forward with his remarkable offer, and with his own resources raised a vast and independent army for the emperor. In April, 1626, he nearly annihilated the army of Mansfeld at Dessau, and pursued him into Hungary, while Tilly in August overwhelmed the king of Denmark at Lutter. Wallenstein returning drove back the Danes into Jutland and their islands, occupied Mecklenburg and Pomerania, and extended his designs to the Baltic, when the walls of Stralsund arrested his career (1628). Peace was made with Christian IV. at Lubeck, May, 1629. The Protestants were everywhere subdued. Ferdinand had proceeded to consummate the work of the Catholic reaction. He issued the edict of restitution, dated March 6 (N. S.), 1629, ordering the surrender by the Protestants of all mediatized church property secularized since 1552, and the transfer to Catholic prelates of all immediate sees held by Protestants against the ecclesiastical reservation, including two archbishoprics and many important bishoprics. This impolitic measure inflamed afresh the Protestant states. Magdeburg firmly resisted its execution.

But the power of Austria and the league was suddenly repressed by a new attack from the north. Ferdinand was combating France in the contest for Mantua. Richelieu, eager to involve him in a foreign war, mediated a truce between Gustavus Adol-phus and Poland, and the Swedish hero came forward to the rescue of German Protestantism. At the very moment of this new danger, the league, exasperated by the conduct of Wallenstein, compelled Ferdinand to dismiss him, and Tilly received the chief command. In June, 1630, Gustavus landed in Pomerania and entered into a treaty with the aged and overawed duke Bogislas XIV., and in January, 1631, concluded a subsidiary alliance with France. John George of Saxony, George William, elector of Brandenburg, and other Protestant princes met at Leipsic in February, 1631, and formed a league of neutrality. William V. of Hesse-Cassel became the bold ally of Sweden. Gustavus forced the imperialists from Pomerania and advanced through Brandenburg, but was unable to prevent the terrible fate of Magdeburg, which on May 10 ( N. S., 20) was stormed by Tilly and Pappenheim. He now compelled the elector of Brandenburg to enter into a treaty, avoided an engagement with Tilly, and restored Mecklenburg to its dispossessed dukes.

Tilly, who had received orders to break up the Leipsic union, attacked Saxony, and drove the mean-spirited elector into an alliance with Sweden. Gustavus marched against him, and on Sept. 7 (N. S., 17), 1631, Tilly sustained a crushing defeat at Breiten-feld near Leipsic. The Catholic power lay prostrate. While the Saxon general Arnheim invaded Bohemia and occupied Prague, Gustavus carried his victorious arms to the Rhino and into Swabia, forced the passage of the Lech, where Tilly was mortally wounded (April 5, 1632), and overrunning Bavaria threatened the Austrian dominions. He was checked by Wallenstein, who, after witnessing with secret joy the misfortunes of the Catholics, had been reinvested by Ferdinand with the supreme command. A new army had arisen at his call. He was joined by Maximilian and Aldringer with the forces of the league, and at Nuremberg the contending armies stood face to face till their ranks wasted away. Then carrying the war northward, they fought a desperate battle at Lutzen, Nov. 6 (N. S., 16), 1632. Gustavus fell, but the Swedes remained masters of the field. Pappenheim was among the slain.

The death of the Swedish king, which was followed by that of the unfortunate Frederick V., spread consternation among the Protestants. But the Swedish chancellor Oxenstiern was equal to the occasion, while generals like Bernhard of Weimar, Horn, Baner, and Torstenson, trained in the school of Gustavus, emulated his deeds. In 1633 Oxenstiern assembled the states of upper Germany at Heil-bronn, and was charged with the conduct of the war. Wallenstein, instead of securing to the emperor the advantages resulting from the death of his great adversary, surprised the world by his inactivity and mysterious conduct. He led his army into Silesia, and confronted the Saxons and Swedes, but wasted the campaign in negotiations. With a devoted army at his command, he was now bent exclusively on schemes of personal ambition. The suspicions of the court were aroused, and his treasonable designs ended in his assassination in February, 1634. (See Wallenstein.) The chief command was transferred to the emperor's son Ferdinand, who, seconded by Gallas and Piccolomini, advanced through Bavaria. He was joined by Charles of Lorraine and a Spanish army, and on Sept. 6 the Protestant forces under Bernhard of Weimar and the Swedish general Horn were nearly annihilated at Nordlingen. This blow was followed by the defection of the elector of Saxony, who in May, 1635, entered into the peace of Prague with the emperor and turned his arms against his recent allies.

The acceptance of the terms of this peace, which sacrificed the Calvinists and Swedes, was to be made compulsory in all the states and enforced by an army of execution. Many of the Protestant states assented or were forced to yield, but Sweden, having no alternative short of relinquishing her conquest, determined to continue the struggle. Richelieu seized the opportunity offered by the depression of the Protestant cause to proinote the aggrandizement of France. He renewed the alliance with Sweden, declared war against Spain, and made Bernhard commander of the French forces. Baner began a series of brilliant campaigns, won a great victory over the armies of John George and Hatzfeld at Wittstock, Sept. 24, 1636, and carried the war into the Austrian territories. In the mean while France was attacked by the Spaniards, the imperialists, and Charles of Lorraine, and John de Weert spread terror to the gates of Paris. In February, 1637, the emperor died, and was succeeded by his son Ferdinand III. The year 1638 opened with the successes of Bernhard, who in February captured John de Weert and other generals at Rheinfelden. In December he took the important fortress of Brei-sach, and outwitted the French by appropriating his conquests.

On his sudden death in 1639, France obtained control of his army, and pressed the war with vigor. Torstenson, a general unsurpassed in the celerity of his movements, who became the Swedish commander-in-chief on the death of Baner in 1641, shook the Austrian throne by repeated invasions, overthrew the archduke Leopold William and Piccolomini at Breitenfeld, Oct. 23, 1642, chastised Christian IV. for his designs against Sweden, completely defeated Gallas in 1644, won a great victory at Jankau in Bohemia, Feb. 24, 1645, taking Hatzfeld prisoner, and marched on Vienna. Rak6czy, prince of Transylvania, advanced through Hungary, and Vienna barely escaped the combined attack. On the side of the French, Guebriant signalized himself at Kempen in January, 1642, and the young duke d'Enghien (the future Conde) beat the Spaniards at Rocroy in 1643. But in November, 1643, the French suffered a great defeat at Tuttlingen in Swabia through the genius of John de Weert. Conde and Turenne retrieved this disgrace near Nordlingen in August, 1645, where Mercy, their eminent adversary, fell. Turenne and Wrangel, the successor of Torstenson, reduced Maximilian of Bavaria, the steadfast ally of Austria, to the last extremity.

Konigsmark, another Swedish general, made himself master of a part of Prague in July, 1648, and the old town, on the opposite bank of the Moldau, had been attacked, though fruitlessly, when on Nov. 3 the news came of the signing of the peace of Westphalia. This peace terminated a struggle which had converted Germany into a vast field of desolation and horror. - As early as 1641 the preliminaries regarding the conduct of the negotiations had been arranged at Hamburg, and Munster and Osna-briick in the circle of Westphalia assigned for the meeting of two separate congresses. At Munster the empire, France, Spain, and the Catholics generally were to negotiate, under the mediation of the pope; and at Osnabriiek the empire, Sweden, and the Protestants, under that of Denmark. But discussions on ceremonial and the varying fortunes of the war caused years to elapse before the congresses could assemble and enter upon earnest deliberations. Denmark and the pope ultimately withdrew, and Venice became the mediator. Separate treaties were concluded at Osnabriick (Aug. 6, 1648) and Munster (Sept. 8), and on Oct. 24, 1648, the definitive signatures were annexed. Nearly every power of Europe was represented. Holland and Switzerland were declared independent of the empire.

France gained Alsace, and was confirmed in the possession of the bishoprics of Toul, Metz, and Verdun. Sweden received Pomerania W. of the Oder, together with Stettin and other towns, the island of Ruigen, Wis-mar, and the secularized sees of Bremen and Verdon; the whole to be held as a fief of the empire, with three votes in the diet. The Swedes were furthermore accorded 5,000,000 thalers. Brandenburg retained further Pomerania, received the secularized sees of Halber-stadt, Minden, and Cammin, and secured the succession to the see of Magdeburg. The elector of Saxony was to retain Lusatia and some minor acquisitions; and the secularized bishoprics of Schwerin and Ratzeburg were allotted to Mecklenburg. The Upper Palatinate with the dignity of elector was confirmed to Maximilian of Bavaria, and an eighth electorate was erected for Charles Louis, son of Frederick V., who recovered the Lower Palatinate. By a singular article the see of Osnabruck was to bo alternately vested in a Catholic bishop and a prince of the house of Brunswick-Luneburg. The possession of the ecclesiastical benefices was placed on the basis of Jan. 1 (N. S.), 1624; and in the case of the Palatinate, Baden-Durlach, and Wurtemberg, the Catholics were obliged to accept 1618 as the normal year.

The treaty introduced an age of more general toleration in Germany. The peace of religion of 1555 was confirmed and extended to the Calvinists, and the equality of the Catholic, Lutheran, and Reformed creeds was established. In all religious questions the Protestants were to have an equal weight with the Catholics in the diet and high courts of the empire. Each state of the empire was to exercise the right of sovereignty, with the liberty of concluding treaties and alliances. The autonomy thus accorded to the states, and the still further diminution of the emperor's authority, weakened the structure of the Germanic body, and paved the way for foreign intervention. The constitutional provisions of the treaty became the fundamental law of the empire. The peace of Westphalia terminated the religious wars of Europe, and forms a grand landmark in its history. The empire had declined into little more than a confederation of states, and the era of French greatness succeeded to that of Hapsburg ascendancy.

Spain acknowledged the independence of Holland, and continued the war against France with disastrous results. - See the histories of the thirty years' war by Schiller, K. A. Menzel (3 vols., Breslau, 1835-'9), Gindely (Prague, 1869), and S. R. Gardiner (London, 1874); also Sir Edward Cust, "Lives of the Warriors of the Thirty Years' War " (London, 1865); Ranke, Geschichte Wallensteins (Leipsic, 1869); and Felix Stieve, Ursprung des dreissigjahrigen Krieges, 1607-1619 (vol. i., Munich, 1875).