The Thirty Years’ War was a 17th-century religious conflict fought primarily in central Europe. It remains one of the longest and most brutal wars in human history, with more than 8 million casualties resulting from military battles as well as from the famine and disease caused by the conflict. The war lasted from 1618 to 1648, starting as a battle among the Catholic and Protestant states that formed the Holy Roman Empire. However, as the Thirty Years’ War evolved, it became less about religion and more about which group would ultimately govern Europe. In the end, the conflict changed the geopolitical face of Europe and the role of religion and nation-states in society. Causes of the Thirty Years’ War With Emperor Ferdinand II’s ascension to head of state of the Holy Roman Empire in 1619, religious conflict began to foment. One of Ferdinand II’s first actions was to force citizens of the empire to adhere to Roman Catholicism, even though religious freedom had been granted as part of the Peace of Augsburg. Signed in 1555 as a keystone of the Reformation, the Peace of Augsburg’s key tenet was “whose realm, his religion,” which allowed the princes of states within the realm to adopt either Lutheranism/Calvinism or Catholicism within their respective domains. This effectively calmed simmering tensions between peoples of the two faiths within the Holy Roman Empire for more than 60 years, although there were flare ups, including the Cologne War (1583-1588) and the War of the Julich Succession (1609). Still, the Holy Roman Empire may have controlled much of Europe at the time, though it was essentially a collection of semi-autonomous states or fiefdoms. The emperor, from the House of Habsburg, had limited authority over their governance. Defenestration of Prague But after Ferdinand’s decree on religion, the Bohemian nobility in present-day Austria and the Czech Republic rejected Ferdinand II and showed their displeasure by throwing his representatives out of a window at Prague Castle in 1618. The so-called Defenestration of Prague (fenestration: the windows and doors in a building) was the beginning of open revolt in the Bohemian states – who had the backing of Sweden and Denmark-Norway – and the beginning of the Thirty Years’ War.
Bohemian Revolt In response to Ferdinand II’s decision to take away their religious freedom, the primarily Protestant northern Bohemian states of the Holy Roman Empire sought to break away, further fragmenting an already loosely structured realm. The first stage of the Thirty Years’ War, the so-called Bohemian Revolt, began in 1618 and marked the beginning of a truly continental conflict. Over the first decade-plus of fighting, the Bohemian nobility formed alliances with the Protestant Union states in what is now Germany, while Ferdinand II sought the support of his Catholic nephew, King Phillip IV of Spain. (The foregoing is taken from a good article in Aug, 2009 issue of History.
A Mighty Fortress: A New History of the German People,
Gordon A. Craig,
Best book on the Thirty Years War:
Geoffrey Parker, et. al.
The Thirty Years War