Thirty Years' War
War is our homeland, our hauberk is our house.
—Soldiers' saying from the Thirty Years' War
First came the Greycoats to eat all my swine,
—Anonymous Poem from the Thirty Years' War
Massive European war raging from 1618 to 1648 (although the French continued fighting the Spanish for a bit longer) involving, directly or indirectly, just about every European power in some fashion. It is usually considered to be the longest recorded continuous war (The Hundred Years' War had a couple of interruptions), and was, until the Taiping Rebellion, the bloodiest war in recorded human history. It was mainly (though not exclusively) fought in the Holy Roman Empire. It famously started with the Defenestration of Prague, the throwing out of two imperial officials from a window (they were unharmed; depending on which side's propaganda you believed, this was either due to divine intervention or their landing in a pile of a substance polite historians call "equine stool", childish ones "horsie poo", and brutally honest ones "horse manure" or "horseshit"). It Got Worse.
The origins of the war are complex, and considering the numerous participants arguably unique to each one of them. The basic conflict involved tensions between Protestants and Catholics inside the Holy Roman Empire, tensions between the emperor and his princes (Protestant and Catholic), tensions between the Czechs and the Germans within The Empire, the old French-Habsburg rivalry, Danish-Swedish rivalry, the Spanish conflict with the Dutch, and Swedish designs on the Baltic. All of these things flowed together to create a 30-year long clusterfuck. The three decades of war are considered to be very important because of the military, social and economic development that it accelerated: Armies in this period became much larger than they had been during the Middle Ages, and new tactics were tried out that would eventually become important.
The war itself was one of the bloodiest and most destructive in human history, killing around 1/3 of the population of the Holy Roman Empire. The unprecedented level of destruction stemmed from the fact that it was the first major gunpowder war, the first war that involved all of Europe, and that the war was fought entirely by mercenary armies. Mercenaries were used so exclusively because gunpowder had made the old knight-based model of warfare obsolete, and nobody had figured out the modern model of professional armies yet. Missing a payment would mean your armies switched over to your enemy. The solders themselves were conscripted. An army would come to town and say, "every man here joins us or we hang you". The ones who joined had to loot farms and towns in order to survive since armies march on their stomachs. Often an entire town had to pool their gold, and bribe the invading army to go away (of course sometimes they'd just take to money and loot anyway). It didn't matter whose side the army was on, to the common peasant, they were the enemy, as a farmer who found an army spending the winter on his lands would find he didn't have enough to feed his family. There were also large groups of civilians (mostly women and children) that were kidnapped from looted towns, and forced to live as servants and prostitutes for the army. Many children were born in the army and never knew anything else when the war ended decades later. Many mercenaries would just desert the army and strike it out on their own as "Freebooters" which more often then not was just a nicer way of saying bandits and highwaymen, thus furthering the plight of the common peasant just trying to live their lives. Add to that the religious dimension of the conflict. A particularly fanatical lord would often decide he didn't like that his neighboring lord was Catholic, or Protestant, or the wrong kind of Protestant, and order his mercenaries to go and genocide his neighbor's peasants even if the majority of said peasants were the same religion as him. Sadly, that's just scratching the surface. Unsurprisingly, many of the greatest works of art depicting the horrors of war have their origin in this nightmare of a conflict, most famously The Miseries and Misfortunes of War By Jacques Callot.
Infamously, the latter half of the war largely degraded into the various participants continuing to fight because they could not afford to stop: It was simply cheaper to keep paying your armies by looting the enemy's lands than paying the severance package. This was eventually solved by having The Emperor pay.
The war once and for all broke any pretense of the Holy Roman Empire being a unified state, cemented France as the dominant power in Europe, and propelled Sweden to the status of short-lived great power. It also made boots fashionable. It concluded with the Peace of Westphalia, two treaties (in Münster and Osnabrück) that involved the Spanish accepting Dutch independence, a blanket pardon for any crimes committed in the war, and some territorial changes; it's sometimes called the "Peace of Exhaustion". The key point, though, was the acceptance that a ruler could choose the religion of his state (the so-called cuius regio, eius religio principle); but those who followed other Christian denominations (Calvinism was covered in this for the first time) could so with some restrictions. This pretty much wrapped up the religious wars of Europe.
The war itself had extremely long-lasting effects, the most notable of which was the Westphalian theory of sovereignty, which is to say the idea that a state has territory, population, a government, and that foreigners do not (directly) interfere in its affairs, leading directly to the modern concept of the nation-state. Indeed, this last point is the real meaning of cuius regio, eius religio: while religious affairs were in themselves important, they also served as a stand-in for the more general displeasure of the German princes at the constant interference of the Emperor and of rulers across Europe at the constant interference of The Pope (it's no coincidence that the Pope tends to drop out of European history textbooks sometime in the 17th century). The Westphalian system continued unchallenged among Western powers until the 20th century, when a few theoreticians attempted to make modifications in response to the atrocities of World War II and the nasty business after The Great Politics Mess-Up (particularly The Yugoslav Wars). Nevertheless, the modern system of states is more or less Westphalian, and several states (particularly China and to a lesser extent Russia) still insist on it.
One of the things that makes the war so maddeningly complicated is that participants had a tendency to go off and fight separate wars whenever they got tired of the main conflict, such as the Danish-Swedish war of 1643-1645.
The back end of the war is largely concurrent with the beginning of the English Civil War, which had similarly wide-ranging long-term effects (for entirely unrelated reasons).
Those wishing to explore this time period more thoroughly in a comprehensive and understandable manner might want to check out C. V. Wedgwood's The Thirty Years' War, if it's still in print and/or a library where you live.
- The Alliance: The Protestants aspired to be this.
- Back From the Brink: Happened quite often due to internal power struggles and shifting alliances breaking up the victor of the hour's momentum.
- Balkanize Me:The Other Wiki terms this a simplified map of Europe at the end. That marble-cake checkerboard in the middle was there before, mind you, but the Peace of Westphalia ending the war cemented it for a long time to come.
- It is simplified - on first glance, it seems to more or less put borders based on rulers, not countries. So several of those large flecks should be made into more pieces as well and cake should have several more pieces in that grey area. Maps like that of whole continent are hard to come by, though, but if one is so inclined, maps of smaller areas might provide better picture painted in many, many colours...
- Armies Are Evil: Most of the (primarily mercenary) armies of any side. Even more so if they were poorly supplied or paid, in which case they took "payment" for their own via the Rape, Pillage and Burn of villages they occupied.
- Crowning Moment of Awesome: Breitenfeldt is officially listed as "The proudest day in the history of the Swedish army." Later the imperial forces would have the Battle of Nördlingen as their own crowning moment of awesome.
- Crowning Music of Awesome: A Mighty Fortress. Technically it was written quite a bit earlier, but it was a Protestant hymn written during the Wars of Religion, of which this was the last.
- Destination Defenestration: The Defenestration of Prague (more exactly, the Second Defenestration of Prague).
- The Empire: How the Habsburg Empire was viewed by its enemies. Not totally deserved nor undeserved.
- Enemy Mine: The Catholic French teaming up with the Protestant Swedes. The Danes and the Imperials (who had been fighting each other earlier in the war!) ended up as allies after the Swedes attacked Denmark.
- Evil Versus Evil: The mercenary armies of any side. Standard procedure was the pillaging of villages, the raping of women and girls, and the torture and/or murder of peasant men and boys. Note that this applied to villages of friend or foe if the army in question grew hungry or restless enough, or was led by bloodthirsty or apathetic commanders.
- Foe Yay: It used to be asserted that The Pope, Urban VIII, when he heard of the death of Gustavus Adolphus, offered a Requiem Mass for the Swedish king. 
- Forever War: Not literally, but in the consciousness of its contemporaries, it came close.
- Gambit Pileup: This is what you get when four or five generation-spanning conflicts decide to intermingle with each other.
- Genre Savvy: The Estate of Peasants of the Swedish Riksdag. They realized that going to war would mean rape, arson, and pillage, and supported Sweden's going to war in Germany on the grounds of "It's better if said activities happen on someone else's turf".
- Gondor Calls for Aid: The Swedish intervention was depicted by its supporters as a mission to save Protestantism from evil Catholic tyranny. It was also traditionally depicted like this in Swedish history books until fairly recently, when the study of history was supposed to imbue the students with a sense of patriotism.
- Grey and Gray Morality: With a very strong hint of Evil Versus Evil.
- Hired Guns: Made up the majority of armies, the most (in)famous would probably be (eventually Duke) Bernard of Saxe-Weimar.
- Hope Spot: The war is infamous for not ending. Time and time again one side seems to be within inches of being able to grasp victory, only for some outside force to tip the balance, forcing another few years of fighting.
- The Horde: One army's marching song was, "We are a horde of ten thousand swine."
- Incredibly Lame Pun: The scribe Philip Fabricius who was thrown out from the Prague Castle window along with his two bosses was ennobled as "von Hochenfall" ("of Highfall") *groan*
- "Join the Army," They Said: This war was fought before law-enforced compulsory military service was standard, so in theory most (not all) soldiers were volunteers. In reality, new recruits were not only made by luring them with (often vain) promises, but also by bullying, threats, or brute force. And once the war left multitudes of people impoverished, starving, or homeless, many joined the armies simply because (even) soldiers were better off than a great part of the populace.
- Knight Templar: A lot of these.
- La Résistance: In several instances, peasants would band together to fight off plundering soldiers - including those of their own "side".
- Moral Event Horizon: Massacres of villages and towns occurred almost from the beginning of the war. The largest and most remembered, however, is the Sack of Magdeburg, committed by the Imperial troops.
- Penal Colony: Germany, effectively. One gets the impression that Europe's monarchs were using this place as a garbage dump to send all their convicts to and let them kill each other in a manner convenient to all honest folk except the civilians who had to have them as guests.
- Persecution Flip: After every campaign there was one. According to the custom of the time a given Prince had a right to decide his subjects' religion. In other words, everyone knew that if their region fell into the hands of a prince from a rival sect, they were likely to be subjected to persecution. Naturally this knowledge was not conducive to peace.
- The Plague: As in most great wars, it did not take long until epidemic diseases began to strike, taking their toll on armies and populace alike.
- Pyrrhic Victory: In the Battle of Lützen in 1632, the Swedes defeated the Imperial army, but lost their King Gustavus Adolphus.
- Rape, Pillage and Burn: The main thing this war is famous for.
- The Starscream: A popular image of Albrecht von Waldstein (a.k.a. Wallenstein or Valdstejn), Generalissimus of the Imperial armies, yet interpretations of his character and actions vary wildly. His convoluted attempts to negotiate peace with the Protestants (and thus, to end the war) on his own terms and without the consent of Ferdinand eventually blew up, whereupon he was charged with high treason, deposed, and assassinated on Ferdinand's behalf. The legitimacy of the treason charge (and with it, his death sentence), the true extent and aims of his secret negotiations, and his ultimate motives have been disputed to this day and still leave much room for speculation and interpretation.
- Spell My Name with an "S": Considering that there was no standard spelling for most European languages at the time, nationalities localize and spell each name differently, and that modern historians pick which among those spellings as they please; it is quite common to encounter several very different spellings for the historical figures when looking through material about the war.
- Sword and Gun: The Finnish hakkapeliitta cavalry.
- War Is Hell: You know the kind of wars that are short, glorious, have clear good guys and bad guys and generally don't cause much trouble? This is not that kind of war. The population of Germany, over the course of the 30 years of war, dropped by 15 to 30%. In some regions, such as Württemberg or Brandenburg more than half of the population was lost.
- Warrior Monk: Catholic commander Johan Tserclaes Count of Tilly, known for his great piety. His battle standard was an image of the Virgin Mary. Subverted by the Cardinal-Infante: He was appointed cardinal despite being never made a priest.
- Wham! Episode: Even as late as the 1950's, Germans rated it was the most destructive event to happen to their country.
- Wild Card: Most of the minor German states switched sides at least once. At least one major one (Bavaria) was infamous for this. Duke Maximilian was often torn between his duty as a good Catholic and his desire to limit the powers of the Habsburg emperor over the princes. Had he taken a firm stand one way or another, the war could have ended much sooner. As it was, he constantly waffled between supporting the emperor and using his position as a counterweight to the obviously ambitious Wallenstein to force his own agenda.
- Worthy Opponent: Gustav II Adolf of Sweden apparently respected Johann Tserclaes, Count of Tilly enough that he set his personal physician to tend to the man's wounds as he lay dying. Tilly, in turn, told the physician, "Your king is truly a noble knight."
- You Have Failed Me...: After the Battle of Lützen, Wallenstein had several officers and soldiers executed for cowardice.
- Wallenstein himself fell as a victim to this trope as the Emperor had him assassinated.
- The Jester's Tale, a Czech movie from 1964 by director Karel Zeman, is set in 1625 Moravia against the backdrop of the Thirty Years' War.
- The film The Last Valley (1971) starring Michael Caine, Omar Sharif and a young Brian Blessed. The score by John Barry is awesome.
- Queen Christina, a 1933 Hollywood film starring Greta Garbo as Christina of Sweden, daughter of Gustavus Adolphus, features the late Thirty Years War as a backdrop.
- Impossible-to-count amount of folk tales (from fairy-tales to legends), songs, art forms (again from paintings to fashion) either refer to this conflict or have roots in it. Surprisingly, it seemed to leave larger impression in these fields than any other conflict later - including both world wars, though this would need some hard data to prove right or wrong.
- Der Abenteuerliche Simplicissimus, written in German in 1668 -- a satirical Picaresque novel about a lad growing up in the middle of the war and conscripted into a military career; probably partially based on first-hand experiences of its author, Hans Jakob von Grimmelshausen. It lampshades the endlessness and pointlessness of the war, but is a good read anyway; also the first modern novel in German literature.
- The poetry of Andreas Gryphius (1616-64), the most important German poet of the Baroque period, is deeply formed by the author's first-hand experience of the Thiry Years War. Despite their age, Gryphius' poems are still standard School Study Media in German schools (making him likely the oldest German author who is invariably covered in literature class).
- The 1632 series by Eric Flint.
- Välskärin kertomukset (The Chirurgeon's Tale) by Zacharias Topelius
- The War Hound and the World's Pain by Michael Moorcock
- German 1910 historical novel Der Wehrwolf (The Warwolf) by Hermann Löns, a revenge-fantasy about North-German peasants who, after having been plundered and brutalized repeatedly by occupying troops, form a guerrilla that routinely ambushes and massacres foraging soldiers. The book is notorious for being a favorite of the Nazis; it directly inspired the terrorist Werwolf guerrilla at the end of World War II. From the other wiki:
"The name was chosen after the title of Hermann Löns' novel, Der Wehrwolf (1910). Set in the Celle region, Lower Saxony, during the Thirty Years' War (1618–48), the novel concerns a peasant, Harm Wulf, who after his family is killed by marauding soldiers, organises his neighbours into a militia who pursue the soldiers mercilessly and execute any they capture, referring to themselves as Wehrwölfe ("Defense-wolves"). Löns said that the title was a dual reference to the fact that the peasants put up a fight (sich wehren) and to the protagonist's surname of Wulf, but it also had obvious connotations with the word Werwölfe in that Wulf's men came to enjoy killing. While not himself a Nazi (he died in 1914) Löns' work was popular with the German far right, and the Nazis celebrated his work. Indeed, Celle's local newspaper began serialising Der Wehrwolf in January 1945."
- Music-wise, Rex Regi Rebellis by the Finnish band Turisas.
- There is also a board game with the name Wallenstein, set in the Thirty Years War.
Theatre & Opera
- As early as 1639 -- five years after the events it fictionalized -- a play Albertus Wallenstein had been written by an English poet Henry Glapthorne about the assassination of Wallenstein, and was performed at the Globe Theatre in London.
- Der Freischütz is set in this period, and the villainous Caspar is a former soldier, and says he learned many knavish tricks from his fellow soldiers.
- Mother Courage and Her Children by Bertolt Brecht
- The Wallenstein trilogy of dramas by Friedrich Schiller.
- The Mass was in reality a Mass of thanksgiving, and the Pope himself wrote,"We give eternal thanks to the Lord of vengeance because he rendered retribution to the proud and shook from the neck of the Catholics their most bitter enemy."