The Battle of Hammaburg Castle was a notable battle during the First Viking War. Taking place in the year 853, it marked the expulsion of the Danes from Frankish territory and the death of Ragnar Lodbrok. It is remembered as one of the most famous battles of the First Viking War. Led by Atticus I himself, the king fought fiercely during the fight, posthumously earning the title 'Atticus Baitelle'.
During the highly successful Rhine Raids, the tide against the Frankish Empire was turned. Byzantine ships forced the retreat of the Vikings from the Rhine River. Many ships were captured and many more were destroyed at the hands of the Byzantines due to their utilization of Greek fire. During this time, the Franks worked on holding the Danes back. When the Rhine Raids died down, the Byzantines and Franks were able to both focus on the marauding Danes. The lines were pushed back to Hammaburg Castle, a fortress constructed by Charlemagne during the Saxon Wars.
The castle was heavily fortified against attack, forcing the Franks and Byzantines to siege the castle. Lines from Jutland were cut as the Franks surrounded the castle. The Danes were trapped in the fortress, allowing the Franks to move in at some point during the autumn months.
The battle began in earnest when a massive breach in the fortress' walls allowed for Frankish troops to enter the city. Atticus, who had brushed off the notion of bombarding the fortress, led a Byzantine Tagma into the city while the Frankish armies followed closely behind. Troops poured into the fortress, trapping the Danes inside of the fortress. At some point during the battle, Atticus I took pause to search for Ragnar Lodbrok, the leader of the Danish invaders. It is said that Atticus located Ragnar while the Viking was bloodied and in a fit of rage. Firsthand accounts claim that Ragnar Lodbrok had been shot with several arrows before attacking Atticus I.
The duel between Atticus and Ragnar resulted in Atticus' victory. The condition of the warlord's body was questionable and there are many accounts regarding the battle. It is known that the Viking was beheaded at some point. Whether Ragnar was killed by decapitation or the beheading occurred post-mortem is speculative. The body was said to have suffered at least a dozen arrow wounds and nine slashing wounds.
Ragnar Lodrok's head was taken to Aachen in a box where it was entombed. The fate of the head and its box following its journey to Aachen is unknown. The Battle of Hammaburg allowed for the Franks to move on Jutland in 856 following the conclusion of the Moravian War, taking the peninsula and forcing the Danes to surrender by 861.