Two days later the king gave orders that the assault upon Landsberg was to be made that night.  The place was extremely strong, and Gustavus had in his previous campaign twice failed in attempts to capture it.  Since that time the Imperialists had been busy in strengthening the fortification, and all the peasantry for ten miles round had been employed in throwing up earthworks; but its principal defence was in the marsh which surrounded it, and which rendered the construction of approaches by besiegers almost impossible.  Its importance consisted in the fact that from its great strength its garrison dominated the whole district known as the Marc of Brandenburg.  It was the key to Silesia, and guarded the approaches to Pomerania, and its possession was therefore of supreme importance to Gustavus.  The garrison consisted of five thousand Imperialist infantry and twelve troops of horse, the whole commanded by Count Gratz.  The principal approach to the town was guarded by a strong redoubt armed with numerous artillery.

Colonel Munro had advanced his trenches to within a short distance of this redoubt, and had mounted the twelve pieces of cannon to play upon it, but so solid was the masonry of the fort that their fire produced but little visible effect.  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.  Their approach was entirely unobserved, and they effected an entrance into the town.

Scarcely had they done so when they came upon a body of three hundred Imperialists who were about to make a sally under Colonel Gratz, son of the governor.  The pikemen at once fell upon them.  Taken by surprise the Imperialists fought nevertheless stoutly, and eighty of the Scots fell under the fire of their musketry.  But the pikemen charged home; Colonel Gratz was killed, with many of his men, and the rest taken prisoners.  Hepburn marching on behind heard the din of musketry and pressed forward; before reaching the town he found a place in the swamp sufficiently firm to enable his men to march across it, and, turning off, he led his troops between the town and the redoubt, and then attacked the latter in the rear where its defences were weak, and after three minutes’ fighting with its surprised and disheartened garrison the latter surrendered.