Margaret I, 1353–1412, queen of Denmark, Norway, and Sweden, daughter of Waldemar IV of Denmark. She was married (1363) to King Haakon VI of Norway, son of Magnus VII of Norway and Sweden. At the death (1375) of her father, her son Olaf became king of Denmark under the regency of his parents. As Haakon was occupied in Norway, Margaret actually wielded the power in Denmark. The death (1380) of Haakon made Olaf king of Norway as Olaf V, and Margaret became regent. She continued to press her late husband's claim to Sweden, and she styled her son king of that country. When Olaf died (1387), Margaret continued to rule Denmark and Norway. In 1389, near Falkoping, Sweden, she defeated and captured the Swedish king, Albert of Mecklenburg. Sweden and Norway were prey to disorder. However, Margaret succeeded in persuading the Danish, Norwegian, and Swedish diets to accept her grandnephew, Eric of Pomerania, as king. He was crowned (1397) at Kalmar, and at the same time a tentative act of union of the three realms was drawn up (see Kalmar Union). Stockholm had held out against Margaret, but surrendered in 1398. In spite of Eric's nominal kingship, Margaret remained the actual ruler of all three kingdoms until her death. She ruled autocratically and energetically, leaving many offices unfilled and reducing others to complete dependence on her authority. Norway and Sweden resented her appointment of Danes to office. The empire built by her was one of the largest of Europe, but it was not lasting.