On 17 July 1647, the defense of the imperial base
Eger in
Bohemia collapsed after attacks by the Swedish besiegers. The advance of the relieving
Imperial army through western Bohemia had been delayed by waiting for the arrival of general
Johann von Werth's defecting Bavarian troops, so that the
Swedish general
Carl Gustaf Wrangel had sufficient opportunity to prepare the defense of the southern approaches to Eger.
Emperor Ferdinand III sometimes accompanied his troops personally on the march, which increased morale. The approaches to Eger were shielded from the south by strong Swedish cavalry and Imperial attacks fizzled out. On 8 August 1647 the Imperial relief force retired to the south and encamped at Křimiz and Tuschkau on the Pilsen plain. General Wrangel pursued the imperial forces and crossed the Königswarter Pass with his army. There he rounded up all the farmers he could find and forced them to expand the entrenchments. Wrangel left a strong garrison there and continued the march south with the main forces. On 13 August he moved into his headquarters in
Plan. The troops camped near St. Anne's Church. To improve security, however, the camp was demolished again and relocated to the nearby Bahuschaberg on 16 August. Ten cavalry regiments and 1,500 infantry now took up positions between the villages of Schlief, Wieschka, Hangendorf and Goldwag on the other side of the Michelsberger Bach. They holed up there and set up a wide ring of field guards around the camp. An ensign with three dozen horsemen was deployed as a crew in Triebl Castle, which is on a steep slope across the stream. General Wrangel had already promised the city fathers of Plan his protection on 14 June. Under threat of severe punishment, he had forbidden his troops to billet, requisition, and pillage. Any use of force against the civilian population should be punished ruthlessly. This letter of protection was an enormous reassurance for the citizens of Plan, as the Swedish army was far from military discipline and order after the death of King
Gustavus Adolphus. The military officials were very busy to punish all offenses. Emperor Ferdinand III had learned of the Swedes' advance south. Fearing the loss of western Bohemia, he ordered his army to march north and attack the Swedish forces. Under the leadership of Commander-in-Chief
Peter Melander von Holzappel and Generals
Raimondo Montecuccoli and
Johann von Werth, who had resigned from the service of Bavaria, the Imperial army advanced and moved via Mies, Schweing and Tschernoschin to the plateau of Wolfersdorf, where it holed up. An advance division, to which Johann von Schwanberg belonged, fought with Swedish troops between Plan and Triebl near the Spittelteich pond. In the course of the bitter struggle Johann von Schwanberg was seriously wounded. ==Prelude==