The war had been going bad for the protestants, until the Swedish king Gustavus Adolphus intervened.
After landing in Pomerania, he fought his way to central Germany.
In November the weather started to worsen and the catholic commander Wallenstein retreated to Leipzig to make winter quarters.
The Swedes were not done yet and chased after him, but their scouts ran into the catholic rearguard.
This held them up and alerted Wallenstein, who recalled the troops he had sent off with Pappenheim earlier.
He deployed his main army in a defensive line near Lützen.
Wallenstein's forces numbered 10,000 infantry, 7,000 cavalry and 24 guns.
Pappenheim commanded a further 3,000 infantry and 2,000 cavalry, but these arrived late in the battle.
Wallenstein stationed all of his guns on a low hill near Lützen, put his pikemen in the center, his cavalry on the flanks and his musketeers in front, along a road.
Gustavus Adolphus commanded 13,000 infantry, 6,000 cavalry and 60 guns.
He too put his infantry in the center and cavalry on the flanks, but kept a sizeable reserve in second line.
There was no tactical shrewdness in the Swedish plan; they intended to just advance and roll over the enemy.
The next morning the Swedish advance got underway slowly because of heavy fog and muddy ground.
One hour before noon the main attack was launched.
The Swedes managed to outflank the protestant left.
Then Wallenstein's assistant Pappenheim arrived with his cavalry and counterattacked.
The tide seemed to turn, but Pappenheim was shot down and the counterattack faltered.
The Imperialists had set fire to buildings in Lützen and thus aggravated the fog with smoke.
Meanwhile both sides poured in reserves to plug holes.
Gustavus Adolphus personally led a cavalry charge on the right wing, however was shot several times and killed.
He did not wear metal armor but leather because of an old wound in his shoulder blade.
In the fog and smoke his death remained unnoticed for a while.
A little later his body was recovered and secretly carried off the battlefield.
In the center the veteran Swedish infantry bravely attacked the well entrenched catholic troops, but were shot to pieces and routed.
However the reserve held firm and officers rallied the frontline.
In the afternoon, four hours into the battle, Bernhard of Saxe-Weimar assumed command.
What followed was a bitter struggle, in which the Swedes finally managed to capture the central catholic gun battery at dusk.
The latter then retreated.
Pappenheim's infantry, who had been marching all day, reached the battlefield just after dark.
They wanted to attack anyway, but Wallenstein estimated that to be too much of a risk and withdrew.
Both sides had lost about 6,000 men, though because the Swedes controlled the battlefield they were able to recover more wounded, stragglers and deserters.
Catholic prestige had been damaged and Saxony was saved for the protestant cause.
But Gustavus Adolphus' death, which was briefed to his soldiers the day after the battle, took the momentum out of the advance and allowed the Habsburgs to recover.
War Matrix - Battle of Lützen
Age of Reason 1620 CE - 1750 CE, Battles and sieges