Margaret I of Denmark

Margaret I brought Denmark, Norway and Sweden under a single ruler at the end of the 14th century and created the Kalmar Union, which bound the Nordic kingdoms together for over a hundred years. Although Danish custom did not expect a woman to rule, she governed all three realms for roughly a quarter of a century until she died in 1412, and is widely counted among the ablest rulers of medieval Europe.

Margaret was born in March 1353 at Søborg Castle, the youngest child of King Valdemar IV of Denmark and Queen Helvig. At six she was promised to Haakon VI, the young king of Norway, whose father Magnus had ruled both Sweden and Norway. The match was part of a contest over the Baltic: Valdemar wanted back Scania, pledged to Sweden since 1332, and his seizure of Scania and of Visby on Gotland led to war with Sweden and the Hanseatic League. The engagement was broken off and then revived, and the ten-year-old Margaret married Haakon in Copenhagen on 9 April 1363. She was raised at Akershus in Norway. In 1364 Swedish nobles deposed Haakon and his father and gave the Swedish crown to Albert of Mecklenburg. Margaret and Haakon's only child, Olaf, was born in 1370.

When Valdemar died in 1375, Margaret secured the Danish throne for Olaf, still a small boy, ahead of her sister's son Albert. On Haakon's death in 1380, Olaf also became king of Norway, and Margaret governed both kingdoms in his name. She showed her skill by settling the long dispute over Schleswig with the counts of Holstein in 1386 on terms that favoured the crown.

Olaf's sudden death at 16 in 1387 changed everything. Margaret was quickly accepted as ruler in Denmark and Norway, and Swedish nobles in revolt against King Albert invited her help. In March 1388 they recognised her as "sovereign lady and ruler" of Sweden. On 24 February 1389 her army defeated Albert near Falköping and took him prisoner. Stockholm, a largely German town, held out with help from Albert's kinsmen and the pirates known as the Victual Brothers until a settlement brokered by the Hanseatic League in 1395; the city passed to her in 1398.

Lacking an heir of her own, Margaret adopted her great-nephew Bogislav of Pomerania, renamed Erik, who was proclaimed king of Norway in 1389 and received homage in Denmark and Sweden in 1396. In June 1397, at a meeting of the councils of all three kingdoms at Kalmar, Erik was crowned king of Denmark, Norway and Sweden. A formal act of union was drafted but never completed, yet the union survived in practice into the early 16th century, and the link between Denmark and Norway lasted until 1814. Erik came of age around 1401, but Margaret remained the real ruler for the rest of her life.

Margaret ruled through officials she chose herself and gave the old councils little room. She took back crown lands that had passed to the nobility and church, issued new coinage, recovered Gotland and much of Schleswig. She placed Danes and Germans in key posts in Sweden and Norway, which later Swedish and Norwegian historians criticised as favouritism, though others see it as a search for loyal administrators. Abroad she avoided entangling wars, refusing an English offer of an offensive alliance; Erik's 1406 marriage to Philippa, daughter of Henry IV of England, sealed only a defensive pact.

In October 1412, during a war with Holstein over Schleswig, Margaret fell suddenly ill aboard her ship in Flensburg harbour and died on 28 October. Her tomb stands behind the high altar of Roskilde Cathedral. Her political talent has rarely been doubted, though her aims have been read in turn as idealistic, nationalist or simply dynastic. Her subjects called her the "Lady King".

Our 1400 map shows the Nordic kingdoms in the years of her rule, and the 1500 map shows the Kalmar Union she founded near the end of its life.