The Thirty Years’ War, fought from 1618 to 1648, was one of the most destructive wars in European history. It was mostly fought in the territories of the Holy Roman Empire and brought incredible devastation to the area, reducing the population by half in some places. Religion was a large part of this war as the Catholic forces wanted to stop the growth of protestant ideas. Though there were other factors too.
As of 1618, Protestant Bohemia was in open revolt against its Catholic king, Ferdinand II. The Bohemian Revolt is famous for the Third Defenestration of Prague when delegates from the Ferdinand were thrown out of a third-story window by the Bohemians when they tried to force the Bohemian nobles to convert. Many of the Holy Roman Empire’s catholic states are dragged into the war as well, and Spain and Austria join up to defeat the Protestants. It is important to note that The Holy Roman Empire (HRE) was not a centralized state like France or China, instead, it was a loose confederation of mostly German states that nominally followed one emperor but had considerable autonomy. Bohemia was also aided by Protestant forces outside the empire, notably the Palatinate, The Bohemian rebels also tried to reach out to protest powers outside the empire such as England and Sweden. The revolt was crushed in 1620 at the Battle of the White Mountain, in which the Catholic forces won a decisive victory led by Johann Tserclaes, Count of Tilly.
Loose fighting continued until 1825, which saw most of the Protestant forces driven out of the HRE. This ended the first phase of the war, The Bohemian Phase. However, Spain had resumed the Eighty Years’ war with The Netherlands (The Dutch had recently gained independence from their Spanish overlords). King Christian, concerned that Protestants would be oppressed severely, decided to enter the war and marched his army down south, this started the second phase of the war, The Danish Phase which lasted from 1625–1630. Christian’s army was subject to multiple defeats at the hands of Tilly and other catholic generals. The Danes were supported by the French, who were Catholic, which meant that this war was about more than religion. The Danish Phase ended when the Danish army was pushed back into Denmark and Christian made peace.
This is all for Part I.
