Upon receiving the news that King Æthelred I of Wessex had died following the battle of Bedwyn, the Danes began to plan a final attack against Wessex, expecting a state of weakness, since Æthelred's brother and successor Alfred was inexperienced as a king. Guthrum's company marched south of Readingum reaching an abandoned fortress called Searesbyrig, near the city of Wiltun. Guthrum and Halfdan Ragnarsson decided to join armies and take Searesbyrig, because of its small distance to Alfred's camp in Wintanceastre.
When they reached Searesbyrig, they found Alfred and the Saxon army waiting for them atop a hill above Wiltun. The commanders and jarls met with Halfdan and Guthrum to discuss a plan, ultimately deciding to reuse the tactic that had won them Bedwyn: Guthrum would attack them from the north and Halfdan from the east, flanking the enemy. The Saxons, however, had a new tactic, instead of separating and meeting the Vikings for an open field battle, they stayed atop the hill. Like in Bedwyn, Guthrum made use of the Hnituðr and crossed the enemy's defense line unscathed.
The Saxons employed archers, but Guthrum's company defended themselves with shields until the barrage of arrows weakened, upon which they pressed on walking up the hill. Reached the top of the hill, they saw their enemies fleeing due west, with Halfdan's army approaching from the east. Guthrum then rejoined Geirmund and said that the vision of him, alone behind enemy lines had prompted Alfred to try and negotiate peace.
- Assassin's Creed: Valhalla (mentioned in Database entry only)
- Assassin's Creed Valhalla: Geirmund's Saga (first appearance)
- Assassin's Creed Valhalla: Geirmund's Saga – Chapter 17
- Assassin's Creed Valhalla: Geirmund's Saga – Chapter 16