Its officers were delighted at the prospect of a change, and, when the party started, Captain Jervoise was proud of the show made by his men, whose active and vigorous condition contrasted strongly with the debility and feebleness evident, so generally, among the Swedish soldiers.
As soon as Marienburg was entered, the men were set to work, to raise and strengthen the rampart and to erect bastions; and they were aided, a few days later, by a reinforcement of two hundred infantry, sent by the king, with some cannon, from the garrison of Derpt.

As the place was surrounded by a morass, it was, ere long, put into a position to offer a formidable defence against any force that the Russians or Saxons might bring against it.
The Swedes engaged on the work gained strength rapidly, and, by the time the fortifications were finished, they had completely shaken off the effects of the fever..