Gustavus had brought from Frankfort as guide on the march a blacksmith who was a native of Landsberg, and this man had informed him of a postern gate into the town which would not be likely to be defended, as to reach it it would be necessary to cross a swamp flanked by the advanced redoubt and covered with water.
For two days previous to the assault the troops had been at work cutting bushes and trees, and preparing the materials for constructing a floating causeway across the mud and water.

As soon as night fell the men were set to work laying down the causeway, and when this was finished the column advanced to the attack.

It consisted of 250 pikemen under Colonel Munro, and the same number of the dragoons under Colonel Deubattel.

Hepburn with 1000 musketeers followed a short distance behind them.
The pikemen led the way, and passed along the floating causeway without difficulty, but the causeway swayed and often sank under the feet of the cavalry behind them.

These, however, also managed to get across.