Thirty Years’ War: The last of the great wars among Christians
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The Thirty Years’ War was a conflict that bloodied Europe in the first half of the 1600s. Considered the bloodiest war the World has ever seen in which about a third of Germany’s population died (an estimated 4.5 to 8 million dead). Also considered the first modern war in history, and took place largely within the Holy Roman Empire from 1618 to 1648.

It begins as a clash over the true faith, i.e., between Christian Catholics and Protestants, but continues with each nation fighting for power, a conflict will give birth to a new Europe.

The spark

waging war in the name of the Christian religion is about as absurd as one could get on the continent where this great religion flourished

The spark that ignited the conflict was generated in Prague, which rebels against the Catholic government by electing a Protestant prince. This is where the famous defenestration, now a tradition of the Czech people in revolt, takes place, throwing governors described as ungodly out the window. So in 1618 the Protestant nobility of Prague decided to throw the emperor’s representatives out the window of the town hall, thus lighting the fuse between Catholics and Protestants. The three despite a flight of about twenty meters were injured but did not die, and so according to the Catholics the Virgin saved them (while others tell that they had fortunately fallen on some manure accumulated on the street below) and from that moment the last of the great wars of religions is considered to have begun, the last one generated by the fire ignited by the Protestant Reformation. At the end of those thirty years of great darkness and evil, anyone in Europe will be convinced of one thing, waging war in the name of the Christian religion is about as absurd as could be done on the continent where this great religion flourished.

The beginning: Cuius regio, eius religio

The Peace of Passau in 1552 ended the Schmalkald War between Protestants and Catholics in the Holy Roman Empire, while the Peace of Augsburg in 1555 sought to prevent future conflicts by fixing existing borders. Under the principle of “Cuius regio, eius religio” (“Whose [is] the kingdom, whose religion [be] he,” i.e., subjects follow the religion of their ruler), states were either Lutheran, then the most common form of Protestantism, or Catholic, depending on the religion of their ruler. Other provisions protected substantial religious minorities in towns such as Donauwörth and confirmed Lutheran ownership of property taken from the Catholic Church starting in Passau.

Yet the agreement was undermined by the expansion of Protestantism beyond the 1555 borders into areas previously dominated by Catholicism. A further source of conflict was the growth of Reformed faiths not recognized by Augsburg, particularly Calvinism, a theology viewed with hostility by both Lutherans and Catholics. Finally, religion was increasingly replaced by economic and political goals; Lutheran Saxony, Denmark-Norway, and Sweden were competing with each other and with Calvinist Brandenburg for the Baltic trade.

Managing these problems was complicated by the fragmented nature of the Empire and its representative institutions, which included 300 imperial estates spread across Germany, the Netherlands, northern Italy, and Alsace and Franche-Comté in modern France. Their size and importance ranged from the seven electoral princes who voted for the Holy Roman Emperor to prince-bishops and imperial cities such as Hamburg. In addition, each belonged to a regional imperial circle, which dealt with defense and taxation and often operated as an autonomous body. Above them was the Imperial Diet (i.e., the Reichstag, the highest legislative body of the Holy Roman Empire), which before 1663 met irregularly and was primarily a forum for discussion rather than legislation.

Although emperors were elected, since 1440 the office was held by a member of the Habsburg family. The Habsburgs, the largest landowner in the Empire, controlled territories with over eight million subjects, including the Archduchy of Austria, Bohemia and Hungary. The Habsburg emperors also ruled Spain until 1556, when it became a separate entity; Spain retained imperial interests, including the Duchy of Milan, and while the two branches of the family often cooperated, their goals did not always coincide. The Spanish Empire was a global maritime superpower whose possessions included the Spanish Netherlands, Milan, the Kingdom of Naples, the Philippines, and most of the Americas. Austria was a land power whose strategic objective was to secure a prominent position in Germany and the eastern border against the Ottoman Empire.

Before Augsburg, religious unity compensated for the lack of a strong central authority; once removed, it presented opportunities for those who sought to weaken it further. These included ambitious imperial states such as Lutheran Saxony and Catholic Bavaria, as well as France, which faced Habsburg lands on its borders to the north, south and along the Pyrenees. Further complicating matters was the fact that many foreign rulers were also imperial princes, involving them in internal disputes; Christian IV of Denmark entered the war in 1625 as Duke of Holstein.

The Age of Iron and Blood

Thus the origins of this long era of “iron and blood” are to be found in the vigor assumed by Protestantism after the Peace of Augsburg (1555), in the determined anti-Protestant attitude of the Church and the Catholic princes under the impetus of the Counter-Reformation, in the conflicts generated in the European balances by Germany’s central position, and then in the political, religious and constitutional tensions within the Empire, manifested as early as the formation in 1608-09 of religiously opposed alliances.

The ruling Habsburgs in Germany and Spain sought to stifle Protestantism, and one by one all European powers slowly became involved. The Holy Roman Empire (ruled by the Austrian emperors of the House of Habsburg) at that time formed the center of Europe (Germany, Switzerland and the Netherlands extending to regions of Italy and France)

Peace of Westphalia and the end of the war

In 1648 the countries involved in the war signed the Peace of Westphalia (a northeastern region of Germany), signing several agreements to resolve both religious and political issues.
In the religious sphere, the Calvinist faith was admitted, as well as the Protestant faith, and the Peace of Augsburg was confirmed, according to which each prince could impose his own religion in the territories under his rule.
Subjects, however, were allowed to privately profess their own religion, a major step toward religious tolerance.

On the political level it was established that:

  • France annexed the territories east of the Rhine;
  • the United Provinces gained recognition of independence from Spain, while Portugal was made independent in 1668;
  • Spain began the slow decline that would lead it to assume a marginal role in Europe, at least until the reconquest of Catalonia in 1652;
  • Sweden obtained the German territories on the Baltic Sea;
  • the Germanic Empire was dismembered into 350 states ruled by princes with full powers, free to make alliances with foreign sovereigns but never against the king. Consequently, thus the Habsburg idea of creating a united empire declined.

In addition to political and religious changes, war in thirty years brought profound negative economic and social consequences. Epidemics, devastation, looting and violence were carried out especially on German territory where there was a drastic decline in population.

Summary: Key Phases

There were mainly two sides in the war:

  1. Habsburg Empire, Spain, Papal States
  2. Bohemia, Denmark, Sweden, France, England

Key Concepts.

  • The Protestant Reformation and the war between Charles V of Habsburg and the German Protestant princes
  • The Peace of Augsburg is too fragile and incomplete a compromise
  • The difficulties of rigid application of the principle of confessionalization
  • The structure, fate and very meaning of empire and imperial dignity in a Europe marked by the development of modern states
  • The Franco-German rivalry

The war is traditionally divided into four phases:

  1. Bohemian phase (1618-25)
  2. Danish phase (1625-29)
  3. Swedish phase (1630-35)
  4. French Phase (1635-48)

Bohemian phase: Clash between the Hussite Bohemians, and Ferdinand of Styria, heir to the emperor and standard bearer of Catholicism
Defenestration of Prague
Bohemian defeat at the Battle of White Mountain
Danish phase: Clash between the emperor and Christian IV, king of Denmark, concerned about the latter’s expansionist aims
Danish defeat
Edict of restitution
Swedish phase: Clash between Gustavus Astulf, king of Sweden, and the emperor
Swedish victory in the Lutz battle
Sweden conquers some territories on German soil
French phase: France’s entry into the war against the Habsburg Empire and its ally: Spain
French victory over the Spanish at the Battle of Rocroi

The conclusion

Peace of Westphalia dates 1648 and ends the Thirty Years’ War. It has five major consequences:

  1. Spain recognizes the independence of the United Provinces
  2. Shift of the imperial axis southward and eastward
  3. Europe devastated by thirty years of war
  4. Balanced situation among the various European powers
  5. End of the wars of religion


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