Kingship
When Margaret's first cousin King Inge the Younger died in 1125, Magnus claimed the throne as the eldest grandson of Inge the Elder. Magnus was recognized by the Geats (Göterna) of Gothenland, but according to the Westrogothic law, had to be accepted also by the Swea, another tribe to the north of the Geats. The Swea, however, had selected Ragnvald Knaphövde. According to Saxo Grammaticus, Ragnvald had shown disrespect towards the Geats by not taking a Geat hostage. As retaliation, Ragnvald was murdered by Magnus's supporters not long after.
Magnus married Richeza, daughter of Boleslaw III of Poland around 1127. In 1130, Magnus backed Boleslaw III in conquering Rügen. The Polish forces together with a Danish fleet compelled the Rani to recognize Polish rule over the island. Magnus is not mentioned as King in the law of Västergötland and was probably ousted from Sweden by his successor Sverker I of Sweden around 1130.
In 1131, Magnus had his cousin and potential rival for the Danish throne, Canute Lavard, murdered, in order to position himself as heir presumptive to his father King Niels. Though he was eventually backed by Niels, Magnus found himself in a civil war against Lavard's half-brother Eric Emune. He died on 4 June 1134 during the Battle of Fotevik in Scania, where his father was also decisively defeated. Niels died later the same year.
Read more about this topic: Magnus I Of Sweden