The Duchy of Holstein was established by a Scandinavian monarch under what union?
Christian I of Denmark Christian I (February 1426 – 21 May 1481) was a Scandinavian monarch under the Kalmar Union. He was King of Denmark (1448–1481), Norway (1450–1481) and Sweden (1457–1464). From 1460 to 1481, he was also Duke of Schleswig (within Denmark) and Count (after 1474, Duke) of Holstein (within the Holy Roman Empire). He was the first Danish monarch of the House of Oldenburg.
Estonia under Swedish rule Estonia under Swedish rule signifies the time between 1558 and 1710, when parts of present-day Estonia (and after 1645 all of the present-day country) were under Swedish rule. In the wake of the breakup of the State of the Teutonic Order, the Baltic German local aristocracy 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 Hiiumaa island; this territory was created the Duchy of Estonia. 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. In 1645, Sweden also conquered the island of Ösel (Saaremaa) from Denmark, and were thus in control of all of present-day Estonia.