Religion was a major factor in the centralization of territories into modern nation states. Religion was crucial in the development of the modern nation state because of it’s ability to be a unifying characteristic. Religion also created common enemies which allowed groups with different religious views separate into individual states that be far more likely to have a more centralized government or monarch. While religion acted as a catalyst in the development of the modern nation state, religion hindered and tore apart developing nation states. Religion played both the role of an asset and a liability in the case of centralization during the age of the reformation.
Religion was successful in creating a common characteristic, by which people categorized themselves. For example, Ferdinand of Aragon and Isabella of Castile reformed Spain by requiring all citizens to be Catholic. This would allow them to have better control and a shared attribute with the citizens of Spain, which would allow for a more centralized territory that would become a nation state. Also during this time period the Calvinists in the Holy Roman Empire area controlled by Philip II were being persecuted for their religion. The common religion in these Dutch provinces allowed for them to form together and create a centralized territory which eventually would become the Dutch Netherlands. German principalities also used their religion as a common characteristic to hold themselves together. When Martin Luther told the German Princes to separate from the Pope and Holy Roman Empire, they unified under Lutheranism which led to the development of that nation state.
While religion was used as a common characteristic, religion was also used to unify groups of people by creating common enemies. For example, William of Orange (William I) centralized the Dutch Provinces, who were primarily Calvinists, against the Holy Roman Empire who was trying to force them to become Catholic. Ferdinand II also tried to use religion to create a common enemy within the Holy Roman Empire, he did this through the Edict of Restitution.
The Edict of Restitution made Calvinists the enemy and unified the Catholics against them and temporarily solidified the Holy Roman Empire as a nation state. Another example of religion creating a common enemy was when Henry VIII created Anglicanism which was against the Pope. This negative disposition towards the Pope strengthened England and allowed the monarch of England to create a more centralized territory, which led to the development of the modern nation state that is England.
While religion was good as bringing nation states together and solidifying them, it also slowed and destroyed developing nation states. For example, the religious diversity that occurred within the Holy Roman Empire led to differences in religion and sect breaking apart until there was no more Holy Roman Empire. Henry of Navarre (Henry IV) saw this problem when he became the King of France and witnessed the religious wars in France between the French Huguenots and Ultra-Catholics.
This slowed the development of France as a nation state, this is because religion was placed ahead of the state. Another example of religion dividing developing nation states was when Philip II attempted to oppress the Calvinists in the Dutch provinces with the Spanish Inquisition. This difference in religion led to the Dutch Revolt and caused the territory to be separated.
Religion was critical in the development and disestablishment of the modern nation state. Religion provided a common characteristic from which a nation state could develop; it also created a characteristic by which a nation state could divide. However, in a majority of the cases the separation was necessary and led to the creation of multiple independent nation states. Religion was both a centripetal and centrifugal force. Religion created created a common characteristic and enemy, which aided the development of the modern nation state, as well as a difference that was a major factor in the disestablishment of developing modern nation states during the age of the reformation.