The discipline and moderation of the Swedish troops formed a great contrast to the reckless behavior of the imperial army. The Swedes left the peaceful inhabitants in undisturbed possession of their lives and property; the strictest order was maintained within the army; each regiment held morning and evening prayers in the open air; gambling, carousing and plundering were sternly prohibited. For these reasons the Swedish king and his army were received by the poor downtrodden people as saviors and liberators. Gustavus Adolphus deeply mourned the fall of Magdeburg, whose fate it had not been in his power to prevent. He took a fortified position at Werben, where the river Havel is joined by the Ube. Tilly entered Saxony with a hostile demeanor, not satisfied with the lukewarm friendship of the elector. Burning villages marked the way of his army. The poor elector, not knowing what to do, in his despair turned to Gustavus Adolphus, whom he had treated so coldly and begged him for help. The king at once was ready to forget past differences, and, joining forces with the elector, he marched toward Leipsic.
Tilly, with 35,000 men, occupied an advantageous position near the village of Breitenfeld, not far from Leipsic, at the summit of a long ridge of sandy hills. The infantry and the greater part of the cavalry were grouped in heavy divisions, forming one single line of battle with artillery behind at the very top of the hills. Tilly himself commanded the centre, while his able and fiery sub-commander, Pappenheim, had the command of the left wing, being in hopes to encounter the Swedish king personally. The Swedish army consisted of 22,000 men, who were joined by 11,000 Saxons.
Early in the morning of September 7, 1631, the Swedes started toward Breitenfeld. Tilly turned pale, it is said, when he saw the order and firmness with which the Swedes marched up to take their positions on the narrow slips of ground between the Lober brook and the reach of the imperial cannon. The Swedes were arranged in a double line of battle, infantry in the centre and cavalry on the wings. Between the squadrons of cavalry divisions of musketeers were placed. The regimental artillery was distributed over a number of places. The king commanded the right wing in person, with John Banér as sub-commander. Teuffel led the centre and Gustavus Horn the left wing. The king had no confidence in the Saxons, for which reason he had arranged them by themselves at some distance to the left of the Swedish army. When everything was arranged, the king rode to the front. With his head uncovered, and his sword pointing to the ground, he prayed: “Almighty God, thou who holdest victory and defeat in the hollow of thy hand, turn thine eyes unto us, thy servants, who have come hither from distant dwellings to fight for liberty and truth, for thy holy Gospel. Give victory unto us for the glory of thy hallowed name! Amen!” The prayer of the king could be heard by almost every man of the army, and all were touched and strengthened by his pious trust in a righteous cause. The Swedes of the right wing were soon attacked by Pappenheim and his cavalry. But the horses of the imperialists were frightened by the flashing fire of the musketeers, and the attack failed to have an effect. It was ended as quickly as it was begun. Pappenheim concluded to make an attempt to surprise the Swedes from the left side. But the king divined his plan. He ordered John Banér with the second line to make a movement by which to turn at an angle with the first and face the attack from the side. Pappenheim was surprised to find a new line facing him. A bloody struggle ensued. Seven times his men made an inroad on the Swedish line and were seven times repulsed, badly damaged by the fire of the musketeers. The Swedes, in their turn, made an attack which scattered Pappenheim’s forces from the field in wild flight.