Plescow (Russo-Swedish Wars).
This fortress was besieged by the Swedes, under Gustavus Adolphus, August 20, 1615, and defended by a Russian garrison. It is notable as marking a departure from the established practice of surrounding a besieged city with walls of circumvallation. For these Gustavus substituted a series of entrenched camps, communications between which were maintained by strong patrolling forces. Little progress was made, owing to a delay in the arrival of the Swedish breaching guns, and through the mediation of England, negotiations were opened with Russia, and the siege raised, October 14, 1615.