The Prince's Wrath
During a time when the Yngling dynasty still held court in Gamla Uppsala, two brothers ruled—Erik the Victorious (Segersäll) and Olof Björnsson—sons of Björn the Old, according to Styrbjarnar þáttr Svíakappa (preserved in the Flateyjarbók from around 1390). The realm was still fragmented, and power rested on a fragile balance between royal authority and the powerful farmers of Uppland.
Styrbjörn was the son of Olof Björnsson of the Yngling dynasty, who reigned around 970–975. His father Olof's father, in turn, was the King Björn mentioned in Rimbert's chronicle of the life of Ansgar, a king who enjoyed an exceptionally long reign on the throne. Olof shared the co-rulership of Svitjod with his brother Erik, the future Victorious, and died according to the Flateyjarbók from a "snakebite"—a traditional euphemism suggesting he may have been poisoned or assassinated by his brother, who coveted sole rule over the realm.
Styrbjörn—who at this time was simply called "Björn" plain and simple—grew up at his uncle's royal estate as a concubine's son (*frilloson*), but for obvious reasons, he refused to content himself with being an overlooked prince in the shadow of power. He believed he possessed the same inherent right to the kingdom as his father, and by the age of twelve, he often sat upon his father's burial mound—an ancient Norse legal claim—and demanded his inheritance. He repeated the demand three years in a row. Erik, a cunning politician, replied that the boy was not mature enough until he reached sixteen. Tension between the uncle and nephew mounted.
The following year, Björn appeared at the great Disting assembly in Uppsala, just thirteen years of age, accompanied by Jarl Ulf. Ulf was likely Erik's governor over Västergötland and the key Göta provinces—regions where Styrbjörn would later find his strongest domestic support. However, he was politically outmaneuvered at the assembly, and the Uppland farmers declared him unfit to take part in the co-rulership until he reached sixteen. At sixteen, a political settlement was reached with King Erik, who summoned the *ledung* (naval levy) and drew from the resources of *Uppsala öd*—the crown estates reserved for national defense that belonged personally to the king of Uppsala. Styrbjörn was granted a fleet of no fewer than 60 fully equipped war-drakes. With at least 32 rowing benches per vessel (translating to a crew of at least 64 warriors per ship), Styrbjörn commanded a force of 3,840 men. This comprised a major portion of the entire national mobilization, which at the time is estimated to have totaled around 6,000 well-armed warriors.
Sitting on a Burial Mound (At sitja á haugi)
Sitting on an ancestor's burial mound was a vital legal and sacral act during the Viking Age. It served as a public proclamation of inheritance and claims to power (*haugóðal*). By physically sitting on Olof Björnsson's mound, the young Björn demonstrated his claim to co-rulership, as custom dictated in Svitjod. His uncle Erik the Victorious opposed this, arguing that Björn's violent and erratic temperament made him unfit to lead the Svear. Erik preferred a unified realm under a single monarch over the ancient system of divided rule, laying the groundwork for the inevitable confrontation.
→ Full childhood account from Styrbjarnar þáttr Svíakappa
According to the Flateyjarbók, during his youth, Styrbjörn was playing with a retainer named Åke at King Erik’s court and threw a cloak over him. In the ensuing scuffle, Åke struck Björn across the nose with a heavy drinking horn. Enraged by the pain and humiliation, Björn slew Åke outside the hall. The *mansbot* (weregild) required for the killing was delivered by Björn directly to King Erik, bypassing Åke's relatives entirely. This made it abundantly clear that he was a self-willed prince who recognized only the supreme authority of the king, indicating early on that he would be a dangerous and difficult man to deal with.
At the assembly (Ting), the free farmers ruled in Erik's favor. Erik gave him sixty fully equipped longships and sent him away for three years "to prevent civil unrest". This was both a punishment and a golden opportunity. Björn departed Svitjod as an exiled prince—but with a formidable fleet.
According to the saga, Björn accepted the fleet with the words: "If I cannot rule the land of my fathers, I shall claim my destiny upon the waves." It was during these three years that he cleared the seas and gathered enough military might and wealth to eventually challenge the rulers of the north. He subjugated Bornholm and raided along the Pomeranian coast, where he quickly drew the attention of local chieftains.
