Swedish Defensive Fortress Warfare in the Great Northern War 1702-1710

In August of 1721, Sweden and Russia concluded the last peace treaty of the Great Northern War. In the treaty, a substantial part of the Swedish Empire was ceded to Russia. Sweden lost Ingria, Estonia, Ösel, Livonia and the southeastern parts of Finland. In peace treaties prior to the treaty with Russia, Sweden had ceded the German province of Bremen-Verden to Hanover and parts of the German province of Pomerania to Brandenburg/Prussia. After more than twenty-two years of defensive warfare, which at times had been turned into offensives, Sweden had lost much of its most valuable territory. Some of the territory had been of the highest strategic value, since it had kept Russia barred from the shores of the Baltic Sea. The losses were the result of concerted attacks, first by Saxony, Denmark and Russia, with Brandenburg/Prussia and Hanover joining later. Poland-Lithuania also became involved in the war against Sweden.
The Great Northern War became one of the more traumatic experiences in Swedish collective memory. The status as a power in Europe was lost, never to be recovered. Among disasters in Swedish early modern history, the Great Northern War compares only to the loss of Finland in 1808–1809. The Great Northern War has not gone unnoticed by historians, quite the opposite. Literature on the war counts well over a thousand titles, and the stream of it goes on. Warfare can be studied on a number of levels, for example, foreign policy and diplomatic levels, levels of domestic politics and leadership, the economic level, the geographical level and the military level. The geographical level dictated the circumstances under which the other levels had to operate. Of the various levels, the military level tends to be decisive, once a war is a fact; other factors will act in support of, or as constraints to, the military level. The military level could be subdivided into the field-army level, the fortress level and the navy level.