Religious Divide in the Holy Roman Empire

The Thirty Years’ War was a series of wars between various Protestant and Catholic states in the fragmented Holy Roman Empire between 1618 and 1648.

Overview

The Thirty Years’ War was a series of wars in Central Europe between 1618 and 1648. It was one of the longest and most destructive conflicts in European history, resulting in millions of casualties.

Initially a war between various Protestant and Catholic states in the fragmented Holy Roman Empire, it gradually developed into a more general conflict involving most of the great powers. These states employed relatively large mercenary armies, and the war became less about religion and more of a continuation of the France-Habsburg rivalry for European political pre-eminence. In the 17th century, religious beliefs and practices were a much larger influence on an average European. In that era, almost everyone was vested on one side of the dispute or another.

The war began when the newly elected Holy Roman Emperor, Ferdinand II, tried to impose religious uniformity on his domains, forcing Roman Catholicism on its peoples. The northern Protestant states, angered by the violation of their rights to choose granted in the Peace of Augsburg, banded together to form the Protestant Union. Ferdinand II was a devout Roman Catholic and relatively intolerant when compared to his predecessor, Rudolf II. His policies were considered heavily pro-Catholic.

The Holy Roman Empire

The Holy Roman Empire was a fragmented collection of largely independent states. The position of the Holy Roman Emperor was mainly titular, but the emperors, from the House of Habsburg, also directly ruled a large portion of imperial territory (lands of the Archduchy of Austria and the Kingdom of Bohemia), as well as the Kingdom of Hungary. The Austrian domain was thus a major European power in its own right, ruling over some eight million subjects. Another branch of the House of Habsburg ruled over Spain and its empire, which included the Spanish Netherlands, southern Italy, the Philippines, and most of the Americas. In addition to Habsburg lands, the Holy Roman Empire contained several regional powers, such as the Duchy of Bavaria, the Electorate of Saxony, the Margraviate of Brandenburg, the Electorate of the Palatinate, Landgraviate of Hesse, the Archbishopric of Trier, and the Free Imperial City of Nuremberg.

Peace of Augsburg

After the Protestant Reformation, these independent states became divided between Catholic and Protestant rulership, giving rise to conflict. The Peace of Augsburg (1555), signed by Charles V, Holy Roman Emperor, ended the war between German Lutherans and Catholics. The Peace established the principle Cuius regio, eius religio (“Whose realm, his religion”), which allowed Holy Roman Empire state princes to select either Lutheranism or Catholicism within the domains they controlled, ultimately reaffirming the independence they had over their states. Subjects, citizens, or residents who did not wish to conform to a prince’s choice were given a period in which they were free to emigrate to different regions in which their desired religion had been accepted.

Although the Peace of Augsburg created a temporary end to hostilities, it did not resolve the underlying religious conflict, which was made yet more complex by the spread of Calvinism throughout Germany in the years that followed. This added a third major faith to the region, but its position was not recognized in any way by the Augsburg terms, to which only Catholicism and Lutheranism were parties.

Religion in the Holy Roman Empire, 1618: Religion in the Holy Roman Empire on the eve of the Thirty Years’ War. Blues indicate Catholic regions and red/orange indicate Protestant (including Lutheran, Calvinist, Hussite, and Reform).

Tension Mount

Religious tensions remained strong throughout the second half of the 16th century. The Peace of Augsburg began to unravel—some converted bishops refused to give up their bishoprics, and certain Habsburg and other Catholic rulers of the Holy Roman Empire and Spain sought to restore the power of Catholicism in the region. This was evident from the Cologne War (1583–1588), in which a conflict ensued when the prince-archbishop of the city, Gebhard Truchsess von Waldburg, converted to Calvinism. As he was an imperial elector, this could have produced a Protestant majority in the college that elected the Holy Roman Emperor, a position that Catholics had always held.

At the beginning of the 17th century, the Rhine lands and those south to the Danube were largely Catholic, while the north was dominated by Lutherans, and certain other areas, such as west-central Germany, Switzerland, and the Netherlands, were dominated by Calvins. Minorities of each creed existed almost everywhere, however. In some lordships and cities, the numbers of Calvinists, Catholics, and Lutherans were approximately equal.

Much to the consternation of their Spanish ruling cousins, the Habsburg emperors who followed Charles V (especially Ferdinand I and Maximilian II, but also Rudolf II and his successor, Matthias) were content to allow the princes of the empire to choose their own religious policies. These rulers avoided religious wars within the empire by allowing the different Christian faiths to spread without coercion. This angered those who sought religious uniformity. Meanwhile, Sweden and Denmark, both Lutheran kingdoms, sought to assist the Protestant cause in the Empire, and wanted to gain political and economic influence there as well.

By 1617, it was apparent that Matthias, Holy Roman Emperor and King of Bohemia, would die without an heir, with his lands going to his nearest male relative, his cousin Archduke Ferdinand II of Austria, heir-apparent and Crown Prince of Bohemia.

War Breaks Out

Ferdinand II, educated by the Jesuits, was a staunch Catholic who wanted to impose religious uniformity on his lands. This made him highly unpopular in Protestant Bohemia. The population’s sentiments notwithstanding, the added insult of the nobility’s rejection of Ferdinand, who had been elected Bohemian Crown Prince in 1617, triggered the Thirty Years’ War in 1618, when his representatives were thrown out of a window and seriously injured. The so-called Defenestration of Prague provoked open revolt in Bohemia, which had powerful foreign allies. Ferdinand was upset by this calculated insult, but his intolerant policies in his own lands had left him in a weak position. The Habsburg cause in the next few years would seem to suffer unrecoverable reverses. The Protestant cause seemed to wax toward a quick overall victory.

The war can be divided into four major phases: The Bohemian Revolt, the Danish intervention, the Swedish intervention, and the French intervention.

Ferdinand II: Ferdinand II, Holy Roman Emperor and King of Bohemia, whose aim, as a zealous Catholic, was to restore Catholicism as the only religion in the empire and suppress Protestantism, and whose actions helped precipitate the Thirty Years’ War.

Bohemian Period

The Bohemian Revolt (1618–1620) was an uprising of the Bohemian estates against the rule of the Habsburg dynasty, in particular Emperor Ferdinand II, which triggered the Thirty Years’ War.

Background

In 1555, the Peace of Augsburg had settled religious disputes in the Holy Roman Empire by enshrining the principle of Cuius regio, eius religio, allowing a prince to determine the religion of his subjects. Since 1526, the Kingdom of Bohemia had been governed by Habsburg kings who did not force their Catholic religion on their largely Protestant subjects. In 1609, Rudolf II, Holy Roman Emperor and King of Bohemia (1576–1612), increased Protestant rights. He was increasingly viewed as unfit to govern, and other members of the Habsburg dynasty declared his younger brother, Matthias, to be family head in 1606. Upon Rudolf’s death, Matthias succeeded in the rule of Bohemia.

Without heirs, Emperor Matthias sought to assure an orderly transition during his lifetime by having his dynastic heir (the fiercely Catholic Ferdinand of Styria, later Ferdinand II, Holy Roman Emperor) elected to the separate royal thrones of Bohemia and Hungary. Ferdinand was a proponent of the Catholic Counter-Reformation, and not well-disposed to Protestantism or Bohemian freedoms. Some of the Protestant leaders of Bohemia feared they would be losing the religious rights granted to them by Emperor Rudolf II in his Letter of Majesty (1609). They preferred the Protestant Frederick V, Elector of the Palatinate (successor of Frederick IV, the creator of the Protestant Union). However, other Protestants supported the stance taken by the Catholics, and in 1617 Ferdinand was duly elected by the Bohemian Estates to become the Crown Prince and, automatically upon the death of Matthias, the next King of Bohemia.

The Defenestration of Prague

The king-elect then sent two Catholic councillors (Vilem Slavata of Chlum and Jaroslav Borzita of Martinice) as his representatives to Hradčany castle in Prague in May 1618. Ferdinand had wanted them to administer the government in his absence. On May 23, 1618, an assembly of Protestants seized them and threw them (and also secretary Philip Fabricius) out of the palace window, which was some sixty-nine feet off the ground. Remarkably, though injured, they survived. This event, known as the Defenestration of Prague, started the Bohemian Revolt. Soon afterward, the Bohemian conflict spread through all of the Bohemian Crown, including Bohemia, Silesia, Upper and Lower Lusatia, and Moravia. Moravia was already embroiled in a conflict between Catholics and Protestants. The religious conflict eventually spread across the whole continent of Europe, involving France, Sweden, and a number of other countries.

Defenestration of Prague: A later woodcut of the Defenestration of Prague in 1618, which triggered the Thirty Years’ War.

Aftermath

Immediately after the defenestration, the Protestant estates and Catholic Habsburgs started gathering allies for war. After the death of Matthias in 1619, Ferdinand II was elected Holy Roman Emperor. At the same time, the Bohemian estates deposed Ferdinand as King of Bohemia (Ferdinand remained emperor, since the titles are separate) and replaced him with Frederick V, Elector Palatine, a leading Calvinist and son-in-law of the Protestant James VI and I, King of Scotland, England, and Ireland.

Because they deposed a properly chosen king, the Protestants could not gather the international support they needed for war. Just two years after the Defenestration of Prague, Ferdinand and the Catholics regained power in the Battle of White Mountain on November 8, 1620. This became known as the first battle in the Thirty Years’ War.

This was a serious blow to Protestant ambitions in the region. As the rebellion collapsed, the widespread confiscation of property and suppression of the Bohemian nobility ensured the country would return to the Catholic side after more than two centuries of Protestant dissent.

There was plundering and pillaging in Prague for weeks following the battle. Several months later, twenty-seven nobles and citizens were tortured and executed in the Old Town Square. Twelve of their heads were impaled on iron hooks and hung from the Bridge Tower as a warning. This also contributed to catalyzing the Thirty Years’ War.

Danish Intervention

After the Bohemian Revolt was suppressed by Ferdinand II, the Danish king, Christian IV, fearing that recent Catholic successes threatened his sovereignty as a Protestant nation, led troops against Ferdinand.

Background

After the Defenestration of Prague and the ensuing Bohemian Revolt, the Protestants warred with the Catholic League until the former were firmly defeated at the Battle of Stadtlohn in 1623. After this catastrophe, Frederick V, already in exile in The Hague, and under growing pressure from his father-in-law, James I, to end his involvement in the war, was forced to abandon any hope of launching further campaigns. The Protestant rebellion had been crushed. Frederick was forced to sign an armistice with Holy Roman Emperor Ferdinand II, thus ending the “Palatine Phase” of the Thirty Years’ War.

Dutch Intervention

Peace following the imperial victory at Stadtlohn proved short lived, with conflict resuming at the initiation of Denmark. Danish involvement, referred to as the Low Saxon War, began when Christian IV of Denmark, a Lutheran who also ruled as Duke of Holstein, a duchy within the Holy Roman Empire, helped the Lutheran rulers of neighboring Lower Saxony by leading an army against Ferdinand II’s imperial forces in 1625. Denmark had feared that the recent Catholic successes threatened its sovereignty as a Protestant nation.

Christian IV had profited greatly from his policies in northern Germany. For instance, in 1621, Hamburg had been forced to accept Danish sovereignty. Denmark’s King Christian IV had obtained for his kingdom a level of stability and wealth that was virtually unmatched elsewhere in Europe. Denmark was funded by tolls on the Oresund and also by extensive war reparations from Sweden.

Denmark’s cause was aided by France, which together with Charles I had agreed to help subsidize the war, not the least because Christian was a blood uncle to both the Stuart king and his sister Elizabeth of Bohemia through their mother, Anne of Denmark. Some 13,700 Scottish soldiers under the command of General Robert Maxwell, 1st Earl of Nithsdale, were sent as allies to help Christian IV. Moreover, some 6,000 English troops under Charles Morgan also eventually arrived to bolster the defense of Denmark, though it took longer for them to arrive than Christian had hoped, due partially to the ongoing British campaigns against France and Spain. Thus, Christian, as war-leader of the Lower Saxon Circle, entered the war with an army of only 20,000 mercenaries, some of his allies from England and Scotland, and a national army 15,000 strong, leading them as Duke of Holstein rather than as King of Denmark.

War Ensues

To fight Christian, Ferdinand II employed the military help of Albrecht von Wallenstein, a Bohemian nobleman who had made himself rich from the confiscated estates of his Protestant countrymen. Wallenstein pledged his army, which numbered between 30,000 and 100,000 soldiers, to Ferdinand II in return for the right to plunder the captured territories. Christian, who knew nothing of Wallenstein’s forces when he invaded, was forced to retire before the combined forces of Wallenstein and Tilly. Christian’s mishaps continued when all of the allies he thought he had were forced aside: France was in the midst of a civil war, Sweden was at war with the Polish–Lithuanian Commonwealth, and neither Brandenburg nor Saxony was interested in changes to the tenuous peace in eastern Germany. Moreover, neither of the substantial British contingents arrived in time to prevent Wallenstein’s defeat of Mansfeld’s army at the Battle of Dessau Bridge (1626) or Tilly’s victory at the Battle of Lutter (1626). Mansfeld died some months later of illness, apparently tuberculosis, in Dalmatia.

Wallenstein’s army marched north, occupying Mecklenburg, Pomerania, and Jutland itself, but proved unable to take the Danish capital, Copenhagen, on the island of Zealand. Wallenstein lacked a fleet, and neither the Hanseatic ports nor the Poles would allow the building of an imperial fleet on the Baltic coast. He then laid siege to Stralsund, the only belligerent Baltic port with sufficient facilities to build a large fleet; it soon became clear, however, that the cost of continuing the war would far outweigh any gains from conquering the rest of Denmark. Wallenstein feared losing his northern German gains to a Danish-Swedish alliance, while Christian IV had suffered another defeat in the Battle of Wolgast (1628); both were ready to negotiate.

Negotiations and the Edict of Restitution

Negotiations concluded with the Treaty of Lübeck in 1629, which stated that Christian IV could retain control over Denmark (including the duchies of Sleswick and Holstein) if he would abandon his support for the Protestant German states. Thus, in the following two years, the Catholic powers subjugated more land. At this point, the Catholic League persuaded Ferdinand II to take back the Lutheran holdings that were, according to the Peace of Augsburg, rightfully the possession of the Catholic Church. Enumerated in the Edict of Restitution (1629), these possessions included two archbishoprics, sixteen bishoprics, and hundreds of monasteries. In the same year, Gabriel Bethlen, the Calvinist prince of Transylvania, died. Only the port of Stralsund continued to hold out against Wallenstein and the emperor, having been bolstered by Scottish “volunteers” who arrived from the Swedish army to support their countrymen already there in the service of Denmark.

Christian IV of Denmark: Christian IV receives homage from the countries of Europe as mediator in the Thirty Years’ War. Painting by Grisaille by Adrian van de Venne, 1643.

Swedish Intervention

The Swedish intervention in the Thirty Years’ War, when King Gustav II Adolf of Sweden ordered a full-scale invasion of the Catholic states, was a major turning point of the war.

Overview

The Swedish intervention in the Thirty Years’ War, which took place between 1630 and 1635, was a major turning point of the war, often considered to be an independent conflict. After several attempts by the Holy Roman Empire to prevent the spread of Protestantism in Europe, King Gustav II Adolf of Sweden ordered a full-scale invasion of the Catholic states. Although he was killed in action, his armies successfully defeated their enemies and gave birth to the Swedish Empire after proving their ability in combat. The new European power would last for a hundred years before being overwhelmed by numerous enemies in the Great Northern War.

Background

The king of Sweden, Gustav II Adolph, had been well informed of the war between the Catholics and Protestants in the Holy Roman Empire for some time, but his hands were tied because of the constant enmity of Poland. The Polish royal family, the primary branch of the House of Vasa, had once claimed the throne of Sweden.

Lutheranism was the primary religion of Sweden, and had by then established a firm grip on the country, but it was not solely the result of religious sentiment that Sweden converted. Notably, one of the reasons that Sweden had so readily embraced it was because converting to Lutheranism allowed the crown to seize all the lands in Sweden that were possessed by the Roman Catholic Church. As a result of this seizure and the money that the crown gained, the crown was greatly empowered.

Gustav was concerned about the growing power of the Holy Roman Empire, and like Christian IV before him, was heavily subsidized by Cardinal Richelieu, the chief minister of Louis XIII of France, and by the Dutch.

Sweden’s Army

During this time, and while Sweden was under a truce with Poland, Gustav established a military system that was to become the envy of Europe. He drew up a new military code. The new improvements to Sweden’s military order even pervaded the state by fueling fundamental changes in the economy. The military reforms—among which tight discipline was one of the prevailing principles—brought the Swedish military to the highest levels of military readiness and were to become the standard that European states would strive for.

The severity of discipline was not the only change that took place in the army. Soldiers were to be rewarded for meritorious service. Soldiers who had displayed courage and distinguished themselves in the line of duty were paid generously, in addition to being given pensions. The corp of engineers were the most modern of their age, and in the campaigns in Germany the population repeatedly expressed surprise at the extensive nature of the entrenchment and the elaborate nature of the equipment.

Swedish Intervention

From 1630 to 1634, Swedish-led armies drove the Catholic forces back, regaining much of the lost Protestant territory. During the campaign, Sweden managed to conquer half of the imperial kingdoms, making it the continental leader of Protestantism until the Swedish Empire ended in 1721.

Swedish forces entered the Holy Roman Empire via the Duchy of Pomerania, which had served as the Swedish bridgehead since the Treaty of Stettin (1630). After dismissing Wallenstein in 1630, from fear he was planning a revolt, Ferdinand II became dependent on the Catholic League. Gustavus Adolphus allied with France and Bavaria.

At the Battle of Breitenfeld (1631), Gustavus Adolphus’s forces defeated the Catholic League led by Tilly. A year later, they met again in another Protestant victory, this time accompanied by the death of Tilly. The upper hand had now switched from the Catholic League to the Protestant Union, led by Sweden.

King Gustav of Sweden: The victory of Gustavus Adolphus at the Battle of Breitenfeld (1631).

With Tilly dead, Ferdinand II returned to the aid of Wallenstein and his large army. Wallenstein marched to the south, threatening Gustavus Adolphus’s supply chain. Gustavus Adolphus knew that Wallenstein was waiting for the attack and was prepared, but found no other option. Wallenstein and Gustavus Adolphus clashed in the Battle of Lützen (1632), where the Swedes prevailed, but Gustavus Adolphus was killed.

Ferdinand II’s suspicion of Wallenstein resumed in 1633, when Wallenstein attempted to arbitrate the differences between the Catholic and Protestant sides. Ferdinand II may have feared that Wallenstein would switch sides, and arranged for his arrest after removing him from command. One of Wallenstein’s soldiers, Captain Devereux, killed him when he attempted to contact the Swedes in the town hall of Eger (Cheb) on February 25, 1634. The same year, the Protestant forces, lacking Gustav’s leadership, were smashed at the First Battle of Nördlingen by the Spanish-Imperial forces commanded by Cardinal-Infante Ferdinand.

Peace of Prague

By the spring of 1635, all Swedish resistance in the south of Germany had ended. After that, the imperialist and the Protestant German sides met for negotiations, producing the Peace of Prague (1635), which entailed a delay in the enforcement of the Edict of Restitution for forty years and allowed Protestant rulers to retain secularized bishoprics held by them in 1627. This protected the Lutheran rulers of northeastern Germany, but not those of the south and west. Initially after the Peace of Prague, the Swedish armies were pushed back by the reinforced imperial army north into Germany.

The treaty also provided for the union of the army of the emperor and the armies of the German states into a single army of the Holy Roman Empire. Finally, German princes were forbidden from establishing alliances amongst themselves or with foreign powers, and amnesty was granted to any ruler who had taken up arms against the emperor after the arrival of the Swedes in 1630.

This treaty failed to satisfy France, however, because of the renewed strength it granted the Habsburgs. France then entered the conflict, beginning the final period of the Thirty Years’ War. Sweden did not take part in the Peace of Prague, and it joined with France in continuing the war.

Swedish-French Intervention

No longer able to tolerate the encirclement of two major Habsburg powers on its borders, Catholic France entered the Thirty Years’ War on the side of the Protestants to counter the Habsburgs and bring the war to an end.

France’s Opposition to the Holy Roman Empire

France, though Roman Catholic, was a rival of the Holy Roman Empire and Spain. Cardinal Richelieu, the chief minister of King Louis XIII of France, considered the Habsburgs too powerful because they held a number of territories on France’s eastern border, including portions of the Netherlands. Richelieu had already begun intervening indirectly in the war in January 1631, when the French diplomat Hercule de Charnacé signed the Treaty of Bärwalde with Gustavus Adolphus, by which France agreed to support the Swedes with 1,000,000 livres each year in return for a Swedish promise to maintain an army in Germany against the Habsburgs. The treaty also stipulated that Sweden would not conclude a peace with the Holy Roman Emperor without first receiving France’s approval.

France Enters the War

After the Swedish rout at Nördlingen in September 1634 and the Peace of Prague in 1635, in which the Protestant German princes sued for peace with the German emperor, Sweden’s ability to continue the war alone appeared doubtful, and Richelieu made the decision to enter into direct war against the Habsburgs. France declared war on Spain in May 1635, and on the Holy Roman Empire in August 1636, opening offensives against the Habsburgs in Germany and the Low Countries. France aligned its strategy with the allied Swedes in Wismar (1636) and Hamburg (1638).

Early French military efforts were met with disaster, and the Spanish counter-attacked, invading French territory. The imperial general Johann von Werth and Spanish commander Cardinal-Infante Ferdinand ravaged the French provinces of Champagne, Burgundy, and Picardy, and even threatened Paris in 1636. Then, the tide began to turn for the French. The Spanish army was repulsed by Bernhard of Saxe-Weimar. Bernhard’s victory in the Battle of Compiègne pushed the Habsburg armies back towards the borders of France. Then widespread fighting ensued until 1640, with neither side gaining an advantage.

However, the war reached a climax and the tide of the war turned clearly toward France and against Spain in 1640, starting with the siege and capture of the fort at Arras. The French conquered Arras from the Spanish following a siege that lasted from June 16 to August 9, 1640. When Arras fell, the way was opened for the French to take all of Flanders. The ensuing French campaign against the Spanish forces in Flanders culminated with a decisive French victory at Rocroi in May 1643.

Continued Swedish War Efforts

After the Peace of Prague, the Swedes reorganized the Royal Army under Johan Banér and created a new one, the Army of the Weser, under the command of Alexander Leslie. The two army groups moved south in the spring of 1636, re-establishing alliances on the way, including a revitalized one with Wilhelm of Hesse-Kassel. The two Swedish armies combined and confronted the imperialists at the Battle of Wittstock. Despite the odds being stacked against them, the Swedish army won. This success largely reversed many of the effects of their defeat at Nördlingen, albeit not without creating some tensions between Banér and Leslie.

After the battle of Wittstock, the Swedish army regained the initiative in the German campaign. In the Second Battle of Breitenfeld, in 1642, outside Leipzig, the Swedish Field Marshal Lennart Torstenson defeated an army of the Holy Roman Empire led by Archduke Leopold Wilhelm of Austria and his deputy, Prince-General Ottavio Piccolomini, Duke of Amalfi. The imperial army suffered 20,000 casualties. In addition, the Swedish army took 5,000 prisoners and seized forty-six guns, at a cost to themselves of 4,000 killed or wounded. The battle enabled Sweden to occupy Saxony and impressed on Ferdinand III the need to include Sweden, and not only France, in any peace negotiations.

Final Battles

Over the next four years, fighting continued, but all sides began to prepare for ending the war. In 1648, the Swedes (commanded by Marshal Carl Gustaf Wrangel) and the French (led by Turenne and Condé) defeated the imperial army at the Battle of Zusmarshausen, and the Spanish at Lens. However, an imperial army led by Octavio Piccolomini managed to check the Franco-Swedish army in Bavaria, though their position remained fragile. The Battle of Prague in 1648 became the last action of the Thirty Years’ War. The general Hans Christoff von Königsmarck, commanding Sweden’s flying column, entered the city and captured Prague Castle (where the event that triggered the war—the Defenestration of Prague—had taken place thirty years before). There, they captured many valuable treasures, including the Codex Gigas, which contains the Vulgate Bible as well as many historical documents all written in Latin, and is still today preserved in Stockholm as the largest extant medieval manuscript in the world. However, they failed to conquer the right-bank part of Prague and the old city, which resisted until the end of the war. These results left only the imperial territories of Austria safely in Habsburg hands.

The Swedish siege of Prague in 1648: In 1648, the Swedish army entered Prague and captured Prague Castle, where the catalyst of the war, the Defenestration of Prague, had taken place thirty years before.

The Peace of Westphalia

The Peace of Westphalia was a series of peace treaties signed between May and October 1648 in the Westphalian cities of Osnabrück and Münster that ended the Thirty Years’ War.

Overview

Over a four-year period, the warring parties of the Thirty Years’ War (the Holy Roman Empire, France, and Sweden) were actively negotiating at Osnabrück and Münster in Westphalia. The end of the war was not brought about by one treaty, but instead by a group of treaties, collectively named the Peace of Westphalia. The three treaties involved were the Peace of Münster (between the Dutch Republic and the Kingdom of Spain), the Treaty of Münster (between the Holy Roman Emperor and France and their respective allies), and the Treaty of Osnabrück (between the Holy Roman Empire and Sweden and their respective allies).

The Ratification of the Treaty of Münster, 1648: The Treaty of Münster between the Holy Roman Emperor and France was one of three treaties that made up the Peace of Westphalia.

These treaties ended both the Thirty Years’ War (1618–1648) in the Holy Roman Empire and the Eighty Years’ War (1568–1648) between Spain and the Dutch Republic, with Spain formally recognizing the independence of the Dutch Republic.

The peace negotiations involved a total of 109 delegations representing European powers, including Holy Roman Emperor Ferdinand III, Philip IV of Spain, the Kingdom of France, the Swedish Empire, the Dutch Republic, the princes of the Holy Roman Empire, and sovereigns of the free imperial cities.

The Terms of the Peace Settlement

Along with ending open warfare between the belligerents, the Peace of Westphalia established several important tenets and agreements:

• The power taken by Ferdinand III in contravention of the Holy Roman Empire’s constitution was stripped and returned to the rulers of the Imperial States.
• All parties would recognize the Peace of Augsburg of 1555, in which each prince would have the right to determine the religion of his own state, the options being Catholicism, Lutheranism, and now Calvinism. This affirmed the principle of cuius regio, eius religio (Whose realm, his religion).
• Christians living in principalities where their denomination was not the established church were guaranteed the right to practice their faith in public during allotted hours and in private at their will.
• General recognition of the exclusive sovereignty of each party over its lands, people, and agents abroad, and responsibility for the warlike acts of any of its citizens or agents. Issuance of unrestricted letters of marque and reprisal to privateers was forbidden.

There were also several territorial adjustments brought about by the peace settlements. For example, the independence of Switzerland from the empire was formally recognized. France came out of the war in a far better position than any of the other participants. France retained the control of the Bishoprics of Metz, Toul, and Verdun near Lorraine, received the cities of the Décapole in Alsace and the city of Pignerol near the Spanish Duchy of Milan. Sweden received Western Pomerania, Wismar, and the Prince-Bishoprics of Bremen and Verden as hereditary fiefs, thus gaining a seat and vote in the Imperial Diet of the Holy Roman Empire. Barriers to trade and commerce erected during the war were also abolished, and a degree of free navigation was guaranteed on the Rhine.

The Holy Roman Empire in 1648: After the Peace of Westphalia, each prince of a given Imperial State would have the right to determine the religion of his own state, the options being Catholicism, Lutheranism, and Calvinism.

Impact and Legacy

The treaty did not entirely end conflicts arising out of the Thirty Years’ War. Fighting continued between France and Spain until the Treaty of the Pyrenees in 1659. Nevertheless, it did settle many outstanding European issues of the time. Some of the principles developed at Westphalia, especially those relating to respecting the boundaries of sovereign states and non-interference in their domestic affairs, became central to the world order that developed over the following centuries, and remain in effect today. Many of the imperial territories established in the Peace of Westphalia later became the sovereign nation-states of modern Europe.

The Peace of Westphalia established the precedent of peaces established by diplomatic congress, and a new system of political order in central Europe, later called Westphalian sovereignty, based upon the concept of co-existing sovereign states. Inter-state aggression was to be held in check by a balance of power. A norm was established against interference in another state’s domestic affairs. As European influence spread across the globe, these Westphalian principles, especially the concept of sovereign states, became central to international law and to the prevailing world order.

Europe in 1648: A simplified map of Europe in 1648, showing the new borders established after the Peace of Westphalia.