Here's a breakdown of his key achievements and the reasons for his fame:
* Danish Viking King: He was the King of Denmark from 986 to 1014.
* Invading England: Sweyn launched numerous raids and invasions of England beginning in 994.
* Overthrowing Æthelred the Unready: After years of warfare, Sweyn's forces were victorious, forcing Æthelred to flee to Normandy in 1013.
* King of England: Sweyn was crowned King of England in 1013, marking the first time Denmark had controlled England.
* Short Reign: Sweyn's reign in England was short-lived. He died in 1014, only a few months after being crowned.
Sweyn's legacy is complex. He was a ruthless warrior and a capable leader, but his reign was brief and marked by violence. He is remembered as a significant figure in Anglo-Danish history, playing a crucial role in the transition of power from English to Danish rule.