Queen of Sweden. Originally Princess of Denmark of the old Estrith Dynasty, she was born about 1278, the daughter of King Eric V Clipping and his young Queen Agnes, an Ascanian Dynasty princess from Brandenburg. In 1286 her father was assassinated at Viborg, and seven years later her mother was remarried to Count Gerard II the Blind of Holstein-Kiel and became the mother of John III the Mild. Betrothed from the age of 2, Margaret, also called Martha, married 18-year-old King Birger of Sweden in 1298 and was then Queen consort, giving birth to Crown Prince Magnus two years later. The royal couple's coronation, the first in Sweden of a king and queen together, was celebrated in 1302 in Söderköping with spectacular tournaments. A formal recognition of little Magnus as Heir to the Throne took place in 1304. After the so-called Håtuna Game revolt in 1306, she and Birger were incarcerated by her rebellious brothers-in-law Duke Eric of Sudermania and Duke Waldemar of Eyland, while her son temporarily was rushed to safety with her brother, King Eric VI Meanwith in Denmark. There was a period of civil war, then reconciliation, but in 1318 Queen Martha and the King Birger had to flee to Denmark when Nyköping Castle was taken by new revolutionaries, and they were deposed. Their son Magnus was then back in Sweden, but barred from the throne, and in 1320 they had the devastating news that he had been beheaded in Stockholm. A younger son Eric, titular Archdeacon of Upsala, had died the year before. Ex-King Birger passed on already in 1321 and his widow outlived him for almost exactly 20 years, remaining in Denmark. They had been given the Spegeborg Estate in Jutland as their Danish residence, but toward the end of her life the ex-queen was a nun at St. Peter's in Næstved, Zealand. She also had two daughters with Birger, Agnes, who became a nun too, and Catherine about whom nothing is known but her name. The contemporary Chronicles of Eric, written by Swedish adversaries, were hateful toward Queen Martha, accusing her and magnate John von Brunkow of instigating the 1318 Nyköping Banquet disaster, resulting in the starvation murder of Dukes Eric and Waldemar, her jailed brothers-in-law.