Field MarshalLennart Torstenson had unexpectedly marched into Jutlandin September 1643. While engaged in operations there, an Imperial army under the command of Count Matthias Gallas ventured north towards Jutland to trap the Swedish army there and destroy it. The Emperor had received requests from Denmark for help, as well as assurance that the Swedish forces were wore down and therefore a fairly easy target. However, since Torstenson thought of Gallas' approaching army of about 15,000 men as a threat to the important Swedish strongholds on the German Baltic coast, he turned his army around and headed south to engage the enemy. Gallas had his troops build and stay behind abatises and entrenchments south of the riverEider in Holstein in an attempt to trap the Swedish forces on Jutland. This tactic failed, as Torstenson's troops outmanoeuvred the enemy by overthrowing a few Imperial positions and pose a threat both to Gallas' back, and Imperial areas further south. The Imperial army began to move south. During the summer of 1644, Torstenson's forces tried to engage the retreating enemy, and in late September, they had once more caught up with the Imperial army. Gallas responded by ordering his troops to build strong defensive positions and await wished-for reinforcement. The Imperial halting-place, south of Magdeburg, was soon surrounded by the Swedish, who cut off all supplies for Gallas' men. Eventually, the Imperial side ran out of bread and they started to lose people to sickness and starvation. As huge numbers of people and animals died, Gallas saw no other solution but to abandon many of the sick, most of his artillery as well as the baggage, and search protection for his troops in Magdeburg itself. The pattern repeated itself when the Swedish forces managed to enclose the city and cut off the supply. One night, the Imperial cavalry made an attempt to break out.
The battle
The Imperial cavalry were caught close to the town of Jüterbog. They were almost wiped out. Out of an initial force of 4,000 soldiers, only a couple of hundred are said to have managed to get away. The Swedish also captured 3,500 horses.
Aftermath
It took a while for the Imperial forces in Magdeburg to succeed with a breakaway. Before they did, they had to turn to eating both cats and dogs as their situation grew more desperate. Many of them deserted. Most of the soldiers who aimed to switch sides and join the Swedish forces were judged to be too weak and were therefore ignored by the Swedish. After getting some help from drift ice that ruined Swedish bridges on river Elbe, Gallas commanded his troops to make a desperate effort to break out of the Swedish encirclement. They managed to escape to Bohemia in the south east. Out of 12,000 Imperial soldiers that constituted Gallas' army in the summer of 1644, about 2,000 men survived. As a result of the severe fiasco the campaign turned out to be, and the tactical mistakes he made, Gallas was relieved from his duty as Imperial commander.
