The Civil War in Denmark (1131-1134), according to Sven Aggesen
If you are looking to learn more about medieval Scandinavia, a good website to visit is the Viking Society for Northern Research. Founded in 1892, the Viking Society has been doing research about the impact of the Norse peoples on the medieval world, publishing a journal and numerous books.
This includes a series of texts and translations of medieval sources, which are offered at affordable prices. For example, The Works of Sven Aggesen contains The Brief History of Danish Kings, which is considered to be the earliest chronicle of events written in Denmark.
We know that the writer, Sven Aggesen, lived in the late 12th-century, and came from a noble family. His account is very much a brief look at Denmark, covering from ancient times to the year 1185. At some points he offers more details in describing events, including the struggle for the Danish throne between Eric II against King Neils and his son Magnus.
Magnus, who had been King of Sweden for a few years before losing that throne, had murdered his cousin Canute Lavard in 1131, proviking Canute’s brother Erik to go to fight against him. King Neils, who is referred to by Sven by his Latin name Nicolaus, decided to support his son, and soon all of Denmark was involved in a civil war.
The historian then proceeds to write about some of the more famous battles that took place during the conflict, which lasted until 1134:
First they fought at Ronbjerg, where Nicolaus won the day, and he captured my grandfather Kristiarn and sent him, bound with iron shackles, to be held in custody at the fort which overlooks the town of Schleswig.
After a while there was another meeting between the contestants at the bridge of Onsild, and although the fighting was even fiercer, Nicolaus’ party prevailed again. Erik’s army turned tail, and he would have been captured on the spot had not Bjorn mentioned above, who was nicknamed Ironside on account of his famous strength, in company with my father Aggi, fought back manfully in the middle of the bridge. They resisted a shower of missiles with such courage that they were thought to be immovable pillars. While defending the way across the bridge, they beat back the enraged attackers with such wonderful valour that they might have crossed the bed of the stream dry-shod on the corpses of the slain. Although hampered by numerous wounds, they did not cease to guard the bridge until the king had embarked on his ships and was ready to escape. They followed him at once and accompanied him in his flight to Scania.
King Nicolaus had now triumphed in two encounters. Therefore he tries to drive his hostile nephew out of the kingdom altogether. He gathered a fleet and pursued him to Scania, where he made a rapid landing at a place which is commonly known as Fotavik and belongs to Lund. The commons of Scania, who are always mightily upright, had called together the entire manpower of the land. This was a well-equipped force, and they had no hesitation in meeting him. Battle was joined, and they hacked and haled to Hades the king’s son Magnus, the perpetrator of the crime previously spoken of, along with two prelates.
And so King Nicolaus was beaten, and bereft of his son and heir at the same time, and he sailed to Schleswig, and the burghers of that city received him with their enclosing walls and treacherously slew him.
King Erik II would himself only rule for three years. You can read A Short History of the Kings of Denmark, translated by Eric Christiansen, as part of his book The Works of Sven Aggesen, Twelfth-Century Danish Historian, which was published by the Viking Society for Northern Research in 1992.