Dominium maris baltici

Baltic Sea in 1219
  Norway
  Sweden
  Conquered by Denmark in 1219 (Pomerania conquered in 1219, lost in 1227. Ösel purchased in 1559, lost in 1645)
The Swedish Empire at its peak in the 17th century
  Sweden under Gustav Vasa, by 1560
  Acquired by Sweden (by 1611), under Vasa's sons
  Acquired by Sweden (by 1654), under Gustavus Adolphus the Great
  Acquired by Sweden (by 1660), under Charles X

The establishment of a dominium maris baltici ("Baltic Sea dominion") was one of the primary political aims of the Danish and Swedish kingdoms in the late medieval and early modern eras. Throughout the Northern Wars the Danish and Swedish navies played a secondary role, as the dominium was contested through control of key coasts by land warfare.