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.
Sophie Elisabeth Pentz Sophie Elisabeth of Schleswig-Holstein (20 September 1619 – April 29, 1657) was a daughter and the eldest child of king Christian IV of Denmark and Kirsten Munk. She shared the title "Countess of Schleswig-Holstein" with her mother and siblings.