Estonia under Swedish rule signifies the period of time between 1561 and 1710, when present-day Estonia was under the rule of the Swedish Empire. In the wake of the breakup of the State of the Teutonic Order, the Baltic German local nobility in the areas of Harrien (Harjumaa) and Wierland (Virumaa), as well as the city of Reval (Tallinn) in June 1561 (and somewhat later Jerwen (Järvamaa)) asked for and were granted protection by the Swedish king Eric XIV, leading to Swedish involvement in the Livonian War. At the conclusion of hostilities in 1583, Sweden was in control of the northern parts of modern Estonia and Dagö (Hiiumaa island); the Duchy of Estonia was created from this territory. Following renewed wars between Poland and Sweden, the southern parts of present-day Estonia (then Livonia) were incorporated into Sweden by the Treaty of Altmark in 1629. Sweden also conquered the island of Ösel (Saaremaa) from Denmark, and were thus in control of all of present-day Estonia.
The time of Swedish rule came to an effective end in 1710, when all the Swedish Baltic provinces capitulated to Russian troops during the end-stages of the Great Northern War. Russian hegemony was formalized in 1721.