The negotiation process was long and complex. The talks took place in two cities because each side wanted to meet in territory under its own control. A total of 109 delegations represented the belligerent States, but not all delegations were present at the same time. Two treaties were signed to end each of the overlapping wars: the Peace Treaty of Münster and the Peace Treaty of Osnabrück.   These treaties put an end to the Thirty Years` War (1618-1648) in the Holy Roman Empire, the Habsburgs (rulers of Austria and Spain) and their Catholic allies fighting on the one hand against the Protestant powers (Sweden, Denmark and some principalities of the Holy Roman Empire) allied with France, Catholic but strongly opposed to the Habsburgs under King Louis XIV. The Swedish intervention during the Thirty Years` War, which took place between 1630 and 1635, was an important turning point in the war, often considered an independent conflict. After several attempts by the Holy Roman Empire to prevent the spread of Protestantism in Europe, King Gustav II of Adolf of Sweden ordered a vast invasion of Catholic states. Although he was killed in battle, his armies managed to defeat their enemies and bring out the Swedish empire after proving their fighting ability. The new European power was to last a hundred years before being overwhelmed by many enemies during the Great Nordic War. After the Protestant Reformation, these independent states were divided between Catholic and Protestant domination, which gave rise to conflicts.
The Peace of Augsburg (1555), signed by Emperor Charles V, ended the war between German Lutherans and Catholics. Peace established the principle of Cuius regio, eius religio („Including the Empire, its religion“), which allowed the rulers of the Holy Roman Empire to choose either Lutheran or Catholicism in the areas under their control, ultimately confirming the independence they had over their states. Subjects, citizens or residents who did not want to adhere to the election of a prince had a time when they could emigrate freely to different regions where their desired religion had been accepted. The Westphalian territory in northwestern Germany gave its name to the treaty that ended the Thirty Years` War, one of the most destructive conflicts in European history. The war was largely fought on German soil, reducing the country to devastation as hordes of mercenaries, not paid by their masters, lived off the land. Rapine, looting and famine haunted the country as armies marched and plundered towns, villages and farms. „We live like animals, eating bark and grass,“ says a pitiful entry in a family Bible from a Swabian village. „No one could have imagined that something like this would happen to us. Many people say that there is no God.
Wenzel Hollar recorded the devastation in the war zone in engravings from the 1630s and hunger reached such a point in the Rhineland that there were cases of cannibalism. .