What was the Thirty Year War and why was it so important?

The Thirty Years' War was a continental European modern conflict that shaped the future of European power and introduced the notion of nation-states.

What was the cause of the Thirty Years War?

There were many contributing factors to the Thirty Years' War but the initial spark was the Defenestration of Prague in 1618.

When did the Thirty Year War end?

The Thirty Years War ended in 1648 with the victory of the French in the battle of Lens. After that, the treaties of the Peace of Westphalia were signed.

What were the results of the Thirty Years War?

The Peace of Westphalia allowed for Calvinism within the Holy Roman Empire. Also, the French and Dutch gained power in Europe at the expense of the Habsburg dynasty.

How many people died in the Thirty Years War?

The death toll of the Thirty Years' War ranges from 4-12 million as a result of starvation and disease. Of this number, around half a million are estimated to have died in battles.

The Thirty Years War

The Thirty Years War Causes

Such a complex continental conflict does not boil down to just one cause but many interlinked ones. First, let's examine some essential terms to allow us to understand the context of the period.

Calvinist

A Protestant follower of the teachings of French John Calvin, who developed the teachings of the original reformer Martin Luther. The Holy Roman Empire did not permit Calvinism before the Thirty Years' War.

Habsburg

The most powerful family in Europe at the time. The Habsburgs had a monopoly on the throne of the Holy Roman Empire for 300 years, between 1440 and 1740. In addition, Habsburgs were ruling Spain, which had control of Italy, Portugal, and the Low Countries.

Low Countries

A collective name for the land which makes up modern-day Belgium, Luxembourg, and the Netherlands.

Lutheran

A Protestant follower of the teachings of German Martin Luther, whose 95 Theses against the Catholic Church began the Protestant Reformation. The Holy Roman Empire permitted Lutheranism before the Thirty Years' War due to the Peace of Augsburg in 1555.

Sovereignty

The ability of a nation to have complete authority over its affairs.

Several complex factors meant that different nations and territories did not see eye to eye in the lead-up to 1618 when the Thirty Years' War broke out.

Cause	Explanation
Spanish and Dutch at war	A religiously charged battle between Habsburg authorities in the Low Countries and Dutch Protestant rebels seeking independence from the Spanish took place during the sixteenth century. The Eighty Years' War between the two had begun in 1568 and continued into the Thirty Years' War after a 12-year truce.
Spanish and French rivalry	The French had fought the Spanish throughout the 16^th century for control of Italy during the Italian Wars. Although France had lost, the rivalry between the countries continued. Europe changed throughout the 17^th century as the Protestant Reformation continued to split nations. This weakened the Habsburg authority, and the French earmarked it as an opportunity to establish their dominance over Europe.
Catholic vs. Protestant	The Protestant Reformation of 1517 sent reverberations across Europe. This meant that Lutheran and Calvinist movements were taking hold in various nations. It polarised European politics. France, Spain, Austria, and parts of the Holy Roman Empire were predominantly Catholic. Meanwhile, other regions of the Empire, England, The Netherlands, and Sweden, were predominantly Protestant.
The Holy Roman Empire	The Holy Roman Empire was a vast mass of land in Central Europe. It was also home to the Protestant Reformation in Saxony. As an entity of many kingdoms and states, the Holy Roman Emperor granted its principalities a measure of power but not full sovereignty that we can recognise today. In 1555, the Peace of Augsburg allowed Catholics and Lutherans to practise their respective beliefs - but any compromise to this treaty would cause trouble!

As we can see, due to the diversity of the different territories within the Holy Roman Empire and continental Europe, the long-standing tensions were bound to come to a head.

The Thirty Years War Key Events

Now we know the various reasons for such a high-scale conflict. Let's dive into the critical events of the period, noting the four distinct phases of the Thirty Years' War.

The Thirty Years War Date

The Thirty Years' War was precisely that. It sparked in 1618 in the Kingdom of Bohemia (within the Holy Roman Empire) and ended thirty years later with the Peace of Westphalia in 1648. Now, let's unpack the key events in each phase.

The Bohemian Phase (1618 - 1625)

The Habsburg, and the future Holy Roman Emperor, Ferdinand II, became the King of Bohemia in 1617. He had allied with the Spanish and ruled territories including Bohemia, Austria, and Hungary. A devout believer, Ferdinand II flouted the Peace of Augsburg and forced all of the citizens to be Roman Catholic.

Defenestration of Prague

In staunch opposition to this, a tradition exclusive to Prague took place. Defenestration already had a precedent in the city. Believe it or not, it refers to throwing political opponents out of the window and occurred in 1419 and 1483.

In the third Defenestration of Prague, three of Ferdinand's Catholic representatives met this fate on 23 May 1618, thrown out of a top-floor window of Prague Castle by an angry Protestant mob. This was the tipping point that initiated the Thirty Years' War.

The Thirty Years War Defenestration room at Prague Castle StudySmarter Fig. 2 Defenestration room at Prague Castle.

Bohemia now craved to be an independent state, and a Bohemian Protestant Army laid siege to Pilsen later that year. Led by General von Mansfeld, they were successful and emboldened against their new king. After Ferdinand II became Holy Roman Emperor in March 1619, the Bohemian Protestant rebels ousted him as their king in November. Protestant ally, Elector of the Palatinate Rhineland region, Frederick V, known as the 'Winter King' for his brief reign, took office.

Control of the region would be wrestled back by Ferdinand II and his Catholic allies in the following year. At the Battle of the White Mountain near Prague in 1620, a Catholic League decisively defeated the Protestant Bohemian forces.

Frederick V lost his crown in Bohemia and his position of Elector in the Palatinate, with Catholic nobles dominating the court in his original region. Defeat at the Battle of the White Mountain led to more Catholic Habsburg victories in the Holy Roman Empire and the Low Countries before 1625.

Did you know? The Catholic League, formed in 1609 in retaliation to the Protestant Union, was a Catholic union in the Holy Roman Empire. Its military leader, the Count of Tilly, was instrumental at the Battle of the White Mountain and during the Palatinate's subjugation.

The Norweigan-Danish Phase (1625 - 1630)

Following these successes, the Habsburg family was in a position of immense strength with their stranglehold over Spain and the Holy Roman Empire. Their opposition was the Protestant regions, including England, the Netherlands, Sweden, Norway-Denmark, Savoy, Venice, and Brandenburg. Catholic France also sided against the powerful family, fearing a Habsburg monopoly.

However, at this stage, only Norway-Denmark was willing to intervene. Their king, Christian IV, was a Lutheran and funded by mercenaries from England and France. He attempted to secure the areas north of the Holy Roman Empire that were growing in Catholic influence. However, defeats at Lutter-am-Barnberg in 1626 and Wolgast in 1628 left him no choice but to accept the Treaty of Lübeck in 1629. Ferdinand II reinstated their prewar borders on the condition that Norway-Denmark's involvement abruptly ended.

Mercenary

A soldier paid to fight for a foreign army.

The Swedish Phase (1630 - 1635)

The Swedes, led by King Gustavus Adolphus, were far more successful. Engaged in a continuing battle with Poland, they were hesitant to get involved in another conflict. After Denmark's humiliation, Adolphus entered the conflict. He displayed his military prowess, driving the Catholic forces and winning the first Battle of Breitenfeld near Leipzig in 1631. Until he died in 1632, his leadership meant that many Protestant forces joined his cause and were in a position of strength. This changed when the Holy Roman Empire struck back at the Battle of Nördlingen in 1634, wiping out Swedish resistance in southern German states.

The 1635 Peace of Prague in the following year disbanded the Catholic League and pardoned the majority of Protestants. This signalled the end of the primary religious element of the Thirty Years' War.

The French Phase (1635 - 1648)

With the Peace of Prague weakening the Protestant regions across Europe, the French entered the war despite their Catholic denomination. Why? They were utterly terrified of Habsburg rule across the entire continent!

The final phase of the Thirty Years' War developed on several fronts. Let's examine a timeline of the critical moments before it finally concluded.

Year	Event
1636	The Protestant Swedes continued fighting the Holy Roman Empire. Catholic France joined them and the Dutch against the Spanish and the Habsburgs. Spain retaliated by encroaching on French territories.
1637	Holy Roman Emperor Ferdinand II died. His son, Ferdinand III, replaced him.
1640	Portugal rebelled against Habsburg Spain in a bid for independence.
1642	The Swedes inflicted another heavy defeat on the Holy Roman Empire at the Second Battle of Breitenfeld. This gave them security in Leipzig, Saxony.
1643	French King Louis XIII died. His son, Louis XIV, became the new monarch, aged only five years old. Merely days after he ascended to the throne, the French claimed a huge victory over the Spanish at the Battle of Rocroi.
1644	With Europe on its knees and exhausted from the most destructive phase of the conflict, peace talks opened.
1648	At the Battle of Lens, France, French general Louis de Bourbon, Prince of Condé, cemented his name into folklore with the final decisive victory of the war. His army obliterated Spanish and Austrian forces.

The French victory at Lens concluded the war. The major participants signed two treaties known as the Peace of Westphalia in 1648.

The Thirty Years War Louis de Bourbon StudySmarter Fig. 3 Louis de Bourbon.

Outcomes of The Thirty Years War

Named after the region where it was born, the Peace of Westphalia encompassed two separate treaties, sealed in the towns of Münster and Osnabrück:

Spanish-Dutch Treaty: This confirmed the creation of the United Provinces of the Netherlands.
Holy Roman Empire, German princes, French and Swedish Treaty: Sweden gained control of the Baltic Sea, and France gained territory in the Rhineland.

In addition to these territorial alterations, the constitution of the Holy Roman Empire conceded sovereignty to German princes, who now had complete control over their lands. Finally, Calvinism became another accepted denomination within the Holy Roman Empire.

The Thirty Years War Summary

After the Peace of Westphalia, there were seismic changes across Europe. The French came to enjoy a period of domination under Louis IV. The Dutch also began demonstrating their authority, with William of Orange becoming King of England after the Glorious Revolution of 1688. As the first modern European-wide conflict, the Thirty Years' War would come to have a considerable impact, along with its result: the primitive birth of nation-states. Historian Jason Farr comments:

The Peace of Westphalia remains the foundation of modern international relations. People still identify themselves based on nationality... Even though the EU, the UN and other international organisations have facilitated globalisation, when it comes to identity, the fact remains that the average person living in France views themselves as French, not 'European'.¹

- Jason Farr

There was also a tremendous human toll in the Thirty Years' War. Total deaths are estimated at between 4 and 12 million, with around half a million lives lost in battle. The excess deaths are a testament to the conditions of starvation and disease within the Empire during the conflict. Some believe that it wiped out 20% of the entire European continent, meaning it was certainly on a scale comparable to the two world wars.

The Thirty Years War - Key takeaways

The Thirty Years' War was a seventeenth-century European conflict that began due to complex religious and political rivalries.
The war had four distinct stages: the Bohemian Phase, the Norwegian-Danish Phase, the Swedish Phase, and the French Phase.
During the first three phases, it was primarily a religiously motivated conflict. But once Catholic France entered the war, it became a matter of power and influence.
With all parties exhausted, the Peace of Westphalia ended the conflict in 1648. The peace agreement helped conceive the notion of modern European nation-states.

References

Jason Farr, 'The Westphalia Legacy and Modern Nation States', International Social Science Review, Vol. 80, No. 3/4 (2005), pp. 156-159.

The Thirty Years War

StudySmarter Editorial Team

The Thirty Years War Causes