Margaret I of Denmark (Margrete I)

Margaret I (Margrete Valdemarsdatter) was one of the most capable and visionary statesmen of medieval Europe, reigning as the undisputed architect of Scandinavian unity. The daughter of King Valdemar IV of Denmark and married at age ten to King Haakon VI of Norway, Margaret demonstrated extraordinary political acumen following the early deaths of her husband and only son, King Olaf.

Acclaimed as 'all-powerful lady and master' of Denmark in 1387 and Norway in 1388, Margaret was invited by rebellious Swedish nobles to liberate Sweden from the unpopular German king Albert of Mecklenburg. Defeating Albert's army at the Battle of Åsle in 1389, Margaret achieved what no monarch had ever done: bringing all of Scandinavia under single sovereign rule. On Trinity Sunday, June 17, 1397, at Kalmar Castle, she had her young grand-nephew Eric of Pomerania crowned king of all three realms, founding the Kalmar Union. Margaret ruled as de facto sovereign for the next fifteen years, maintaining internal peace, curbing the greedy German Hanseatic League, and regaining the island of Gotland.