Thirty Years' War (1618-1648) - One of the most intriguing and least understood wars in history, it began as a conflict between Catholics and Protestants in Central Europe.  But by the time it was over, it had transformed into a war for political supremacy between two of the most powerful royal dynasties in Europe, the Habsburgs and the Bourbons.  The Protestant Reformation was the real catalyst, as it led to the fragmentation of the already tenuous confederation of states that made up the Holy Roman Empire.  The spark that ignited the situation into open warfare is known as the Defenestration of Prague.  It was on May 23, 1618 when two representatives of the new emperor-elect, Ferdinand II, arrived in Prague (the capital of Bohemia) to administer his edicts.  The problem is that Ferdinand was fervently Catholic and Bohemia was staunchly Protestant.  The Bohemian assembly greeted the representatives by tossing them out a third story window of Hradschin Castle.  The event quickly triggered the Bohemian Revolt which is considered the beginning of the war.  The following year the sitting emperor, Matthias, died and the revolts spread into other regions of the empire.  Ferdinand II proved to be a weak emperor and was unable to end the uprisings.  In 1620 he was forced to ask for assistance from his Habsburg cousin, King Philip III of Spain.  This was a momentous decision for it expanded the conflict outside the borders of the Holy Roman Empire.  Not only that, but it reignited the Eighty Years' War between Spain and the Netherlands which has been in the midst of a twelve year truce.  And finally, it drew the attention of Louis XIII of France.  Louis was a member of the House of Bourbon which was the Habsburgs' most powerful rival; but with the entry of Spain into the war, France found itself surrounded on both sides by warring states.  King Philip died only a year after coming to Ferdinand's aid, but his son, Philip IV, kept Spain involved in the war.

 

About the same time, things heated up in Eastern Europe as well.  Prince Gabriel Bethlen of Transylvania, a Protestant, made an alliance with Osman II of the Ottoman Empire to protect against Hungary.  This prompted Bohemia, the region where the war began, so seek the Ottomans as a protectorate against the Holy Roman Empire and its partner Spain.  The Ottomans agreed in exchange for tribute from Bohemia.  The Habsburgs tried to offset this new threat from the east by using Poland as a buffer.  Poland supported the Habsburgs and went to war with the Ottomans.  Within only a couple years, a revolt which began in Bohemia spread across most of Europe.  In the meantime, Poland managed to hold up the Ottomans long enough to keep them from coming to Bohemia's aid.  Bohemia fell to the Holy Roman Empire in November, 1620 at the Battle of White Mountain.  The first phase of the Thirty Years' War concluded in 1625.  This is called the Palatinate Phase (named for a region in Bavaria).  The second phase lasted from 1625 to 1629 when Denmark entered the war against the Holy Roman Empire (thus it is called the Danish Phase).  King Christian IV, a Protestant, was worried the empire's success in the first phase might threaten Danish sovereignty.  After three years of fighting, the empire had been largely successful against Denmark, but was unable to knock it out completely.  So the two sides agreed to a truce in 1629 by signing the Treaty of Lübeck.  In 1630 Sweden entered the war for the same reason Denmark had five years earlier (and is likewise called the Swedish Phase).  King Gustavus Adolphus, another Protestant, had much greater success than Denmark had though.  He regained much of the territory lost by the Protestants in the first two phases.  It should be noted that Cardinal Richelieu of France provided substantial support to both Denmark and Sweden in their efforts against the Holy Roman Empire.  Even though he was Catholic, as was France, his primary concern was to keep the Habsburgs from becoming too powerful.  France's alliance with Sweden proved effective and Adolphus won the Battle of Breitenfeld in 1631.  It was the first major Protestant victory over the Catholic League in the war.  Sweden followed up with a second victory at Lützen in 1632; however, King Adolphus was killed.  Without him, the Scandinavians lost the Battle of Nördlingen in 1634. The Swedish Phase ended in 1635 with the Peace of Prague.

 

The final phase saw the direct intervention of France into the war (and is called the French Phase).  Richelieu worried that an imperial victory would leave the Habsburgs in too powerful of a position.  So France declared war on both Spain and the Holy Roman Empire in 1635.  It began very badly for France.  Spain became the aggressor and invaded French territory, ravaging several territories in the southwest.  But after about a year, the French got their war legs and halted the Spanish at Compiègne.  Then in 1637, Emperor Ferdinand II died, and his successor and son, Ferdinand III had little appetite for continuing the war.  The fighting dragged on though and in 1640, the tide turned clearly in France's favor when it captured the fort at Arras.  With that, peace negotiations began in 1641, but stalled until Richelieu died in 1642.  Then the following year, King Louis XIII died and his five year-old son, Louis XIV, became king.  Now most of the original antagonists were gone and their replacements were looking to bring the war to a conclusion.  The Second Battle of Nördlingen was fought in 1645, with the victory going to France and her Protestant allies.  The imperial army lost its most experienced general, Franz von Mercy, leaving it in dire straights.  The last major battle of the war was at Zusmarshausen, a combined French-Swedish victory over the Holy Roman Empire on May 17, 1648; two days after the Treaty of Münster was ratified.  The second half of the Peace of Westphalia was ratified later that year ending one of the strangest wars in Europe's history.