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  • James Houser

September 7, 1631 - The Thirty Years' War & the Battle of Breitenfeld

Updated: Jun 13, 2021

September 7, 1631. After five hours of desperate fighting with pike, musket, saber and cannon, the Swedish army of King Gustavus Adolphus stands victorious at the Battle of Breitenfeld – the climax of the Thirty Years’ War. While it is only the latest miserable chapter in one of history’s most miserable conflicts, the combat has truly initiated a new age of warfare: the transition from medieval to modern.

I once asked my wife what she thought the Thirty Years’ War was about, and she said “About 30 years,” and while that is not helpful it is true. While I would be extremely happy to explain every detail of how the Thirty Years’ War came to happen, you are not here for my ranting about Bohemian religious laws or dynastic struggles in southwest Germany. So I’m going to do this thing again where I vastly oversimplify and explain a huge conflict as briefly and concisely as possible:

The Thirty Years’ War (1618-1648) started out as a political and religious conflict within the Holy Roman Empire (modern Germany/Central Europe) between Austria and the Catholics on the one hand and an alliance of Protestant princes on the other. Like a piece of wire accidentally left in the washing machine, eventually every country in Europe got sucked into the mess for one reason or another – religious, political, personal, dynastic. By the midpoint of the war, it wasn’t even a religious war anymore, since both warring sides had an assortment of Protestant and Catholic powers in either alliance, and by the last decade it had mainly turned into an excuse for Catholic France to beat up also-Catholic Austria and Spain.

The Thirty Years’ War was also the most devastating conflict Europe had ever seen. Gob-smackingly huge armies of mercenaries pillaged and looted their way across central Europe, ruining vast swathes of Germany, France and Poland. Millions of people died of starvation, disease, exposure or straight-up murder in the loose maelstrom of chaos, and by the end of the war Germany had lost half of its population. The Thirty Years’ War is on a level with the Black Plague as one of the greatest catastrophes in European history, and the personal accounts of the war resemble some of the most harrowing chronicles from the Black Death or the World Wars.

One anonymous poem read:

"First came the Greycoats to eat all my swine,

Next came the Bluecoats to make my sons fight,

Next came the Greencoats to make my wife whore,

Next came the Browncoats to burn down my home.

I have naught but my life, now come the Blackcoats to rob me of that."

So yeah, seems like a party. On to our story.

The Thirty Years’ War had been raging for twelve years, and had gone universally badly for the Protestants. Almost all the major Protestant powers had been forced to capitulate, and by 1630, their cause was on its last legs. The Catholic armies of Bavaria, led by the Count of Tilly, had defeated the Protestant mercenary bands in central Germany. Meanwhile, General Albrecht von Wallenstein and his Imperial forces had defeated the King of Denmark and pushed all the way to the Baltic Sea. It really did seem like the war was finally over: the Catholics were completely victorious all across the Empire, with only a few Protestant towns still holding out, and there was no one around to interfere. The only exception was the King of Sweden, who had just landed at the port of Stralsund with an army, but no one thought he could accomplish much. What the hell is Sweden, anyway?

King Gustav II Adolf of Sweden – Latinized as Gustavus Adolphus – did not have much of a reputation yet. A devout Protestant and ardent supporter of the Protestant cause in the Thirty Years’ War, he had wanted to help out his religious brethren in northern Germany. For most of the 1620s, though, he had been distracted by his long-running war with Poland. He was also sending out diplomatic feelers to gauge support for his intervention in the war, seeing as the Protestants were getting beaten every which way and he didn’t want to be alone and exposed if he did make a landing.

Having secured a number of Protestant German princes who said they were ready to repudiate their terms of surrender – and having secured a very hefty subsidy from the French, who always liked making trouble for Austria – Gustavus landed the Swedish army in northern Germany in 1630. Again, the Catholic powers were not very concerned, since Gustavus didn’t have a high reputation and his army was quite small relatively speaking.

The Swedish Army, though, was unlike any other force in Europe. European militaries were still in the transitional period from medieval to modern, a transformation that some historians have since called the “military revolution.” The emergence of gunpowder weaponry had made the obligation-based chivalric armies of the Middle Ages obsolete, but no one had yet figured out how to replace them. The sudden importance of well-trained infantry, long artillery trains, skilled siege engineers and professional commanders found every state in Europe lacking. While some very wealthy countries like France or Spain began to build professional armies from scratch, a standing army was exorbitantly expensive even for them. The cost of war had ballooned even as it became more complex and deadly.

The short-term solution was the mercenary company, a preexisting organization of professional soldiers skilled in the art of gunpowder warfare. It was much more cost-effective for European powers to just…hire an army for the duration of the war, then cut them loose when the war was over. From around 1450 to 1650, it was the “age of the mercenary” in European warfare, and these mercenaries helped generate a lot of the destruction of the Thirty Years’ War. Countries went bankrupt all the time, so mercenary companies were often cut loose in foreign lands where they just did whatever they wanted. Not a recipe for stability in the best of times; during the general famine, disease, and chaos of the Thirty Years’ War, it was a recipe for apocalypse.

The Swedish Army was different. King Gustavus Adolphus had built a military system within his own, relatively poor country of Sweden that was to become the envy of Europe. While he would be forced to use mercenaries in his later campaigns, the core of the Swedish army in Germany was its home-grown regiments. Gustavus’s military reforms included tight discipline, a complex logistic structure, a trained officer corps, state-issued uniforms, retirement pensions, and a military police system that dished out capital punishment for looting, pillage, and violence against women.

Gustavus also made the Swedish army a model of tactical performance. Unlike the tight pike blocks of most contemporary infantry, the Swedes had a regimental system that fought in linear formations and delivered tight musket volleys. Rather than the ineffectual skirmishing of heavily armored, pistol-armed cavalry, Gustavus trained his lighter cavalry to charge at a devastating gallop. Instead of the large, cumbersome artillery of most armies, Gustavus had lighter, more maneuverable guns that could be moved around the battlefield easily. On top of all this, he had a modern engineer corps and the first semblance of a staff. All of these changes were institutional rather than technological, a case of applying new organizations and ideas to preexisting tools – the result of King Gustavus’ indomitable energy and fertile mind.

This system, though, hadn’t had the chance to show itself yet. Unimpressed by the small advance force Gustavus brought to Germany, the Catholic leaders had dismissed the untrustworthy General Wallenstein, and Tilly’s Catholic League army had gone to Italy to crush a Protestant uprising there. In 1630, then, Germany was wide open for the Swedish intervention. The only reason Gustavus delayed as long as he did was the necessity of finance – waiting for the French subsidies to come in, raising additional loans, accumulating supplies in his base at Stralsund, and bringing in the tax receipts for 1629 and 1630 before the final move could be made.

By summer of 1630, though, Gustavus had begun to secure himself on the German coast, retaking numerous cities from the Catholics and haranguing the Protestant powers to rise up in his support. Despite their promises, very few of the Protestant princes that had pleaded with Gustavus to intervene now came out in support. Now that Sweden was really in the Thirty Years’ War, no one wanted to stick their necks out, and soon Gustavus’ army was hemorrhaging money and eating away all his carefully stored rations.

By the winter of 1630-1631, it looked like the Swedish intervention in Germany would be a bust. Gustavus had depended on raising allies and receiving financial and material support from his fellow Protestants, who he had come to liberate; instead, he had received nothing but sullen looks and closed purses. The military situation was temporarily in his favor after Wallenstein’s dismissal and in Tilly’s absence, but that was about to change, since Tilly had come back north during the winter.

In May of 1631, Tilly and the army of the Catholic League came roaring north to drive this upstart Protestant King into the sea and finally end the Thirty Years’ War with a resounding Catholic victory. Their first target would be the great German city of Magdeburg, whose town council had been literally the only power in Germany to declare their early support for King Gustavus. Tilly besieged the city, and on May 20 captured and brutally sacked it. The Sack of Magdeburg was the single worst atrocity of the Thirty Years’ War and certainly the most widely recorded one; practically the whole city was destroyed by fire and 24,000 men, women and children butchered.

The Sack of Magdeburg was a terrible moral defeat for the Catholic side, since it sent the previously reluctant Protestant lords scrambling into the arms of Sweden. One of the most reluctant but strategically important of these princes was John George, the Elector of Saxony, a Protestant ruler who was nevertheless part of the Catholic coalition. The mere indication that John George was looking to declare neutrality, though, was enough to bait Tilly into a pre-emptive invasion of Saxony, and by the first days of September Tilly had captured Leipzig. He was not able to do to Leipzig as he had done to Magdeburg, though, because the savior had come. Gustavus Adolphus – the “Lion of the North” – would confront the "Butcher of Magdeburg" on the field of Breitenfeld.

Breitenfeld was to be the largest battle of the Thirty Years’ War. King Gustavus of Sweden brought 22,000 men to the field, accompanied by the reluctant 18,000 Saxon troops of John George. They were confronted by the mercenary machine that had chewed up and spat out one Protestant army after another in the last decade: Count Tilly’s Catholic League army of 31,000 men. While Tilly was surely outnumbered, he knew that the Saxons were reluctant allies of the Swedes at best, since John George was nothing if not weak-willed and always willing to change sides.

Both armies lined up on the field at Breitenfeld on September 7, 1631. Tilly and Gustavus both placed all their infantry in the center, flanked with cavalry on the wings. The Catholic army, which formed in the great masses of pikemen, 50 wide and 30 deep, was flanked by small squads of musketmen: this formation was known as the “tercio.” The Swedes, on the other hand, drew up in a novel formation of two distinct lines with a substantial reserve behind them. The Swedes’ light guns were interspersed within the line, rather than the Catholic concentration in one big mass right behind their infantry. Unlike the Catholic units – which had separate arms working entirely apart - the Swedes’ infantry, cavalry and artillery were all trained to work together rather than apart.

Tilly attacked first, with his glacial tercios slowly advancing towards the Swedish-Saxon line. His aim was to crush his Protestant opponents between two flanking movements as he had done at Wimpfen in 1622. He sent his cavalry forward on his left, only to have that force collide with Gustavus and his combined arms on the wing. The Catholic cavalry was not prepared for a combination of light artillery and infantry to be mixed in with their opposite numbers, and soon suffered high losses and fled from the field. In the meantime, though, Tilly’s tercios had crunched over the Saxon forces and sent them fleeing from the battlefield in disarray, opening a wide gap in the Protestant lines. The routed Saxons made straight for the Swedish baggage train, which they proceeded to ransack. Some allies.

With the Saxons gone, Tilly now had the advantage of numbers, and tried to turn his tercios against the Swedish left, uncovered by the Saxon flight. If the Swedish left had collapsed, the result would have been disaster; Gustavus was on the other side of the battlefield dealing with the cavalry battle, and most other armies would have been swallowed up by Tilly’s attack. The more flexible Swedish system, its superior command structure, and its better training prevented this from happening. The general on the spot saw what had happened to the Saxons and bent his front back 90 degrees so that it resembled an L shape. Tilly’s tercios ran into a wall of volley fire, and the Swedish light guns were able to change position rapidly and come to reinforce.

As Tilly’s infantry reeled under the disciplined fire of the Swedes, Gustavus had been running off the Catholic cavalry. With that threat eliminated, he wheeled his half of the army inwards and charged the Swedish cannon with his own horsemen. Unable to retreat or quickly change the bearing of their heavy, bulky pieces, the Catholic gunners were cut down where they stood. The Swedes seized their opponents’ artillery, and thanks to their own gunners riding double behind the cavalrymen, they were soon turning Tilly’s cannon on the backs of his own infantry.

Stranded in the open and faced with fire from both front and rear, the Catholic army disintegrated. Overconfident in his army and convinced that he would scatter the Swedes and Saxons in a single formidable shock, Tilly had failed to provide a reserve or second echelon to his force. This had proved sufficient to almost win the battle by defeating the demoralized Saxons, but was no match for the superior tactics, structure and professionalism of the Swedish army. In the end, as the tercios of Tilly’s old-style army melted away, the elite military spirit of the Swedish brigades carried the day.

After five hours of combat, Breitenfeld was a decisive Swedish victory, the most famous battle of the war and the first significant Protestant victory since the war had begun 11 years ago. Tilly lost almost half his army to death, capture or desertion. The Swedes took 19 cavalry flags and 80 infantry colors, showing just how badly the Catholic rout had become. Gustavus Adolphus, the avenging Lion of the North, had his revenge for Magdeburg.

Of course, the war did not end there. Gustavus spent the rest of 1631 overrunning Germany, undoing 13 years of Catholic victory, but soon outstripped his own resources. The tides of war turn against everyone eventually, and Gustavus’ luck ran out in 1632 when he was killed at the Battle of Lutzen. But he had reversed the tide of the war just when it seemed to be over. The Catholics would never get as close to victory as they had been before 1631, and after Sweden’s and then France’s entry into the war it would be the Protestant/French forces on the attack from here on out. In essence, Gustavus had tried to save Germany, but just ended up prolonging the agony for everyone. The war that could have ended in 1630 would last another 18 years.

More importantly in the long term, though, everyone and their brother scrambled to copy the Swedish system that had performed so brilliantly at Breitenfeld. Gustavus Adolphus’s legacy would not be a triumph in the Thirty Years’ War, but the modernization he brought to the European military art. Combined arms, advanced logistics, mobile field artillery, professional officers, the engineer corps – all of this would be adopted and used by countries from here on out. The age of mercenaries was finally over: they had become too expensive and hard to control for years, but Gustavus finally showed the Europeans a better way to wage war.

In central Germany on September 7, 1631, warfare went from medieval to modern.

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