Sweden entered the Thirty Years' War in 1628 in an attempt to prevent the Holy Roman Emperor Ferdinand II from expanding his power to the Baltic Sea and threaten Swedish territory.

Against the background of the strengthened position of the Emperor and the Catholic side, the Edict of Restitution was issued in March 1629, which would have brought a killing blow to the independence of the Protestant states.

It was against this background, as well as after the signing of the separate treaty with Poland in September 1629, that Gustavus Adolphus, King of Sweden, planned his own intervention in the war and came to be a leading figure for the Protestant co-religionists in Northern Germany.

[17] Through the Treaty of Stettin, concluded on 25 August, Duke Bogislav XIV of Pomerania was forced to enter into an alliance with Gustavus Adolphus and assist with supplying the King's army.

[18][19][20] At the beginning of his campaign, Gustavus Adolplhus was in great need of both economic and military support from the Protestant powers in Germany, whose enthusiasm for the Swedish landing was extremely limited.

Half of these troops, under the direct command of the King, captured the town of Ribnitz and some minor imperial fortresses before launching a siege of the port city of Rostock.

Meanwhile, on 23 October his ally William of Hesse-Kassel was defeated by the Imperial Field Marshal Gottfried Heinrich Graf zu Pappenheim, whose troops had arrived in the lower reaches of the Elbe.

[45] The Swedes turned the sack of Magdeburg to good use: broadsides and pamphlets distributed throughout Europe ensured that prince and pauper alike understood how the Emperor, or at least his troops, treated his Protestant subjects.

The Swedes conducted an immediate counter-attack which in a week drove Pappenheim's troops back to the other side of the Havel, while also capturing the strategically important bridgehead of Tangermünde.

The King's confidence was strengthened by the fact that the Swedish scouts had underestimated the strength of the imperial troops, although he viewed the combat readiness of the Elector's allied Saxon army with great skepticism.

After a two-hour long march, the King's troops arrived at the Lober stream, whose swampy banks they were forced to cross with great difficulty to reach the neighboring village of Podelwitz.

[85][83][86] Generalfeldmarschall Tilly was in command of the Imperial-League centre, which included 18,700 troops, with General of the Artillery Otto Friedrich von Schönburg auf Wesel as his second-in-command.

As soon as Pappenheim's cuirassiers approached Gustavus Adolphus' front and discharged their pistols at them, the Swedish commanded musketeer platoons fired a concentrated volley at point-blank range.

[95][96][97] Following Pappenheim's seventh repulse at about four o'clock in the evening, Gustavus Adolphus ordered Banér to rally the cavalry of Sperreuth, Stenbock, Soop, Tott, Stålhandske and Wunsch.

The Finnish horsemen met stubborn resistance, forcing Banér to bring in Ortenburg's cuirassiers and the Yellow Brigade's commanded musketeers at five o'clock, who pulverised the tercio with musketry fire and canister charges from their regimental artillery.

[105][110][111] Tilly's plan was that his centre would launch a broad frontal assault on Horn's open left flank, with fire support from the Imperial batteries on Galgenberg and the captured Saxon artillery.

[114][103][112] Horn was well aware that his thin lines alone could not hold their ground against the crushing force of the Imperial-League infantry, which now numbered some 20,000 men and reinforced by thousands of Fürstenberg's cavalry.

While Tilly slowly regrouped his tercios for his decisive infantry assault, he wanted to put pressure on Horn by sending Fürstenberg's remaining cavalry, mainly Baumgarten's and Cronberg's cuirassier regiments, in several columns to attack the Swedish left wing from the flank and the rear.

Horn responded to Tilly's regroupment by having Baudissin's and Caldenbach's cuirassiers engage in delaying actions against the Imperial-League infantry, with fire support from Waldstein's musketeers.

As Teuffel was about to carry out the King's order, he was killed by a stray bullet fired from Tilly's infantry regiment, who advanced to confront the stationary Blue Brigade.

Isolani's Croats employed the caracole to stall the Green Brigade, but they were repulsed by heavy musket volleys and canister shots from Hepburn's regimental guns.

In a short time they were able to fire concentrated platoon volleys, which together with the canister shots from their regimental guns inflicted mounting casualties on Pappenheim's advancing columns.

[119][120][121] First (saith he), giving fire unto three little Field-pieces that I had before me, I suffered not my muskettiers to give their volleyes till I came within Pistollshot of the enemy, at which time I gave order to the first rancks to discharge at once, and after them the other three: which done we fell pell mell into their ranckes, knocking them downe with the stocke of the Musket and our swords....[Tilly] received a horrible, uninterrupted pounding from the king's light pieces and was prevented from coming to grips with the latter's forces.At the same time, Göss' tercios clashed with Eckstädt's brigade and Erwitte's reserve cavalry advanced against Horn's cavalry.

[125][126][121] The fierce fighting along Horn's front accumulated thick clouds of gunpowder smoke and dust, which with strong westerly winds spread across the entire battlefield.

[124] The repeated and concentrated volleys from Horn's and Hepburn's musketeers, coupled with the heavy cannonade from their regimental artillery, forced the remnants of the Imperial-League infantry to stall their attacks, leading to the men being crowded together and losing their momentum.

[128][130][121] At this point, Tilly had been wounded in the chest and neck by three musket bullets, and received two blows to the head by a German officer, belonging to the Rheingrave's regiment, who attempted to capture him.

[133][134][135] "The battaile thus happily wonne, his Majesty did principally under God ascribe the glory of the (first) victory to the Swedes and Fynnes horsemen, who were led by the valorous Fieldt-Marshall Gustavus Horne; for though the Dutch horsemen did behave themselves valourously divers times that day, yet it was not their fortune to put the enemy to flight; and though there were brave brigades of Swedes and Dutch in the field, yet it was the Scots brigads’ fortune to have gotten the praise for the foote service, and not without cause, having behaved themselves well, being led and conducted by an expert cavalier and fortunat—the valiant Hepburne.

The King's army then continued down the Main, reached its outlet in the Rhine, crossed the great river, and captured the Electoral residence of Mainz on 11 December 1631, where they established their winter quarters.

By the month's end, Hanover, the Hessian dukes, Brandenburg and Saxony were officially aligned against the empire, and France had agreed to provide substantially greater funding for Gustavus Adolphus' armies.

[159] In addition to the musketeers' volley fire and agility during battle, Gustavus Adolphus also used regimental guns that accompanied the troops during their advance and provided devastating firepower at close range.