The Twenty-Five Years' War Part I: Europe 1618-1631
The twenty-five year war would at the time be the most devastating conflict known to the European continent. The conflict, initially religious and local, would over the years become increasingly political and international.
The conflict would begin in the Holy Roman Empire of Germany. The latter had not known war since the Peace of Augsburg in 1555. This peace had put an end to the religious wars between Catholics and Reformed and created the principle of "Cuius regio, eius religio" (like Prince, like religion). They allowed the states of the Holy Roman Empire to choose their religion freely, the inhabitants having to either convert or emigrate. This peace, however, did not put an end to religious tensions in the empire. In 1606, the incident at Donauwörth, where Catholics were banned from practising their religion, provoked the intervention of the Duke of Bavaria, Maximilian I, sent by the Holy Emperor Rudolf II, seeking to restore freedom of worship. The Duke of Bavaria banned Protestant worship in the city, which in reaction provoked the creation of the Evangelical Union by the Protestant princes, headed by Frederick IV of the Palatinate to defend their interests. In response, the following year saw the creation of the Holy Catholic League led by Duke Maximilian I.
In 1609, Emperor Rudolf II, after losing his titles of Archduke of Austria and King of Hungary to his brother Matthias, granted freedom of worship in Bohemia to ensure the loyalty of his subjects. This did not prevent Matthias from being elected King of Bohemia in 1611. He became Emperor Matthias I after the death of his brother the following year. In 1617, the Bohemian crown went to Ferdinand II, a fervent defender of the Catholic faith. His religious positions provoked the hostility of Bohemian Protestant nobles.
On May 23, 1618, two representatives of Ferdinand II and their secretary were defenestrated by Protestant nobles at Prague Castle. Although they survived their fall (which the Catholics would consider a miracle), the great Bohemian Protestant nobles present at the defenestration and fearing Ferdinand II's reaction, rose up. Thus began the revolt that marked the beginning of the conflict.
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On the left the Duke of Bavaria Maximilian I. On the right the Holy Emperor Ferdinand II.
1) The Bohemian and Palatine period
In 1619 Emperor Matthias died and his titles went to Ferdinand II who became Holy Emperor. Ferdinand II had Cardinal Klesl, on whom old Matthias had relied to lead the empire, arrested. The cardinal sought to reconcile the revolts and the Habsburgs, realizing that the empire had neither the money nor the means to quell the revolt. The confrontation becoming inevitable between the two camps, Ferdinand II to avoid disaster will ask for help from the Habsburgs of Spain. The latter could not and did not have the means to intervene, so Ferdinand II turned to the Duke of Bavaria Maximilian I.
The Bohemian revolts were also looking for allies, but were rejected by many Protestant princes and monarchs, and even by the Protestant Union, which wanted to be defensive and could not intervene in the internal affairs of the House of Habsburg. The Protestant nobles finally recruited the leader of the latter, Frederick V of the Palatinate, in exchange for the Bohemian crown. The emperor was stripped of his title of King of Bohemia and Frederick V became King of Bohemia. But the latter will only be King for one winter. On November 8, 1620 the Protestant rebels were crushed at the Battle of White Mountain. The conflict did not end, however, because in exchange for his support of the Emperor, Maximilian of Bavaria demanded the titles and territories of Frederick V, the electorate of the Palatinate. This was no longer an internal affair in the Habsburg domains, but an attack on a principality protected by the Protestant Union. In 1621 the leaders of the Bohemian revolt were executed and the Protestant Union was dissolved. However, some principalities and mercenary troops were still active, the most important being Christian of Brunswick. A Catholic but anti-Habsburg general, Ernst Von Mansfeld, led the Protestant forces and together with the elector of Baden in Mingolsheim defeated Tilly, generalissimo of the Catholic League on 27 April 1622. The latter took his revenge in Wimpffen and Höchst in May and June 1622, ravaging the region in the process. It was at this point that the conflict was exported abroad. Mansfeld intervened in the conflict between the Spanish and the United Provinces by supporting the latter in the siege of berg-op-Zoom in October of that year. With General Spinola's forces repelled, the Spanish garrisons on the Rhine began to move.
The Protestants will be crushed in August 1623 at the battle of Stadtlohn which will see the entry of Spain into the conflict. France worried about this situation will support and push the Kingdom of Denmark to enter the conflict at the end of 1624.
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Frederick V, Elector of the Palatinate King of a Winter.
2) The Danish period
Christian IV enters the conflict. A Protestant monarch, he is king of Denmark as well as Duke of Holstein, the title by which he is vassal of the Holy Emperor. He used this title to commit himself to protect the interests of the Protestants in the empire but at the same time to expand his kingdom and influence in the circle of Lower Saxony. Copenhagen seeks to ensure the preservation of the bishoprics won by the Protestants since the Augsburg War. Denmark also has views of the rich city of Hamburg, the great economic centre of northern Germany. Taking advantage of the absence of Sweden, occupied with the kingdom of Poland, Christian IV of Denmark brings his troops into the Holy Roman Empire and war. But the lack of coordination with the other Protestant states in the north of the Holy Roman Empire led to the isolation of the Danish forces cut off from his human and financial support.
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Christian IV, King of Denmark.
At the Battle of Dessau in April 1626, Mansfeld was defeated by a new imperial commander, Albrecht von Wallenstein. Mansfeld, after fleeing to Hungary, fell ill and lost his life. General Tilly defeated the Danes at the Battle of Lutter in August 1627 and Wallenstein after his pursuit of Mansfeld defeated them at Wolgast in September 1628. This victory allowed him to approach Berlin and keep Brandenburg away from the conflict and to occupy the Baltic Sea by freeing the subjects of Mecklenburg from their rebellious duke under the Emperor's orders. The war seems to be over after the occupation of Jutland, which pushes Denmark to peace.
The Peace of Lübeck puts an end to the conflict between Ferdinand II and Christian IV, the latter can only intervene in the affairs of the empire as Duke of Holstein and not as King of Denmark. Although he loses no land, Christian IV is forced into a forced neutrality which he cannot leave. At the same time, spurred on by his victories, Ferdinand II will issue an edict of restitution of the property of the secularized Church by the Protestant princes. This restitution will push the latter to rise up against the emperor violating the conditions of the Peace of Augsburg.
Before the Peace of Lübeck, Wallenstein continued to administer the Mecklenburg while seeking to create a fleet in the Baltic in the service of the Empire. Thus the cities of the Hanseatic League were placed at the service of the Emperor. The city of Stralsund refused and Wallenstein laid siege to it. In spite of fierce resistance, the city could not receive the help of the waiting Denmark [1] and the city fell at the end of May 1628. This capture of the city will push the Swedes to accelerate their entry into the war.
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Stralsund under siege by the imperials.
3) The Swedish period
On July 1, 1629, after signing an armistice with Poland, Sweden led by its King, Gustav II Adolphe landed in the city of Peenemünde. The imperials were busy helping Spain in the Netherlands and fighting France in the War of Succession of Mantua in northern Italy, but were slow to react. In addition, the dismissal of Wallenstein in September, unpopular at the Viennese court and increasingly seen as too powerful by the Emperor, deprived him of a competent soldier to arrest the Swedes. Moreover the financing of the Swedish army by Richelieu from Paris allows the establishment of a powerful army strongly underestimated by the imperials. In addition the dismissal of Wallenstein allows the release of many mercenaries to be added to the army of the northern lion. Gustav II Adolf of Sweden urged the Elector of Brandenburg to join him in the war before descending to the south and taking Frankfurt on the Oder in April 1631. But the imperials pull themselves together and make peace with France at Cherasco, putting an end to the War of Succession in Mantua. Tilly in May 1631 takes the Protestant city of Magdeburg after a siege that lasts since November. The rich city was pillaged and destroyed, with more than 15,000 dead [2]. The preventive attack of Saxony by the imperials will push the prudent ally of Vienna, the Saxon elector Jean-George, into the Swedish camp. After a defeat at Havelberg [3] against Gustav II Adolf, Tilly's armies were defeated by the Swedes at Breitenfeld.
This battle opposed 42000 Swedish and Saxon against 37000 Catholics and took place north of Leipzig. After artillery exchanges of 12h and 14h between the two sides, Tilly to prevent his Tercios from being further decimated by the powerful Swedish artillery sent his cavalry from his left wing commanded by Pappenheim against the Swedish right. At the same time he attacks the Swedish left occupied by the Saxons. The Swedish wing repulses Pappenheim's cavalry with efficiency but the Saxons, troops not very seasoned troops are sunk, they get out of the way by abandoning artillery and equipment. As victory could only come from his right, Tilly set his centre in motion to take advantage of the breach in the Swedish position. But some of his troops went in pursuit of the Saxons hoping to plunder their baggage and the Tercios in his centre only slowly redeployed and had to abandon their heavy artillery. Gustav II Adolphe rebuilt a line of halt in front of the Tercios while harassing them with his light artillery much easier to redeploy than that of Tilly. Suddenly at 5pm, the Swedish right led by the King of Sweden himself diagonally crosses the entire battlefield capturing the defenseless Catholic artillery. The Swedish infantry massed against the Spanish Tercios and the captured artillery was turned against their former owners. Tilly's army collapsed against the Swedes, Tilly managed to escape with a tiny fraction of his troops [4]. The imperials lost more than 20,000 soldiers, half of them killed and the other half taken prisoner by the Protestants. The Swedes suffered only 4,000 casualties.
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Gustav II Adolf during his triumph at Bretenfeld.
The North Lion suffered the first real defeat for the imperials since the beginning of the conflict, and this victory will allow him to federate the Protestant cause and to relaunch the conflict in favor of the Protestant cause in the Holy Empire. However, the end of the conflict is still a long way off and total victory is far from assured.
[1] OTL the Scottish and German reinforcements sent on May 8 by Christian IV were already delayed and did not arrive until May 24. ITL they were even further delayed and the city fell without Danish and Swedish reinforcements.
[2] "Slightly" less than OTL or Tilly's armies caused more than 20,000 casualties. However, this does not change the nature of the massacre, which still remains a rallying cry for the Protestant cause.
[3] In the battle of Werben OTL, the location changed just slightly because of the butterflies.
[4] OTL he was wounded and died from this wound because of his frail health and old age.
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Very big chapter I wrote. I've done a lot of research on the Thirty Years' War and I hope you like the result. Feel free to comment and give your opinion. Many thanks to
@alexmilman who enlightened me on many points about the Thirty Years War as well as
@Basileus_Komnenos for his support since the beginning of my chronology (have a look at his chronologies, he does a very good job).