The Second Battle of Yorktown was a decisive battle that was part of the Great Heathen army's English campaign and that ended in a Viking victory. After having trapped the Saxons in the town and made them believe the Vikings were gone, Ivar and his warriors emerged from under the town and the tunnels to attack the dismayed Saxons, wreaking havoc and inflicting heavy casualties on the Saxons. The Saxon army, severely depleted and having lost Bishop Heahmund, who was captured in the proceedings by Ivar, retreated and left their camp outside York, demoralized and helpless.
The Vikings, to the great surprise of the Saxons, had apparently left the town and marched back to their ship. Heahmund and Aethelwulf opened the doors of the cathedral only to find it was empty, with a horse inside and some rats crawling on the door, which made Heahmund suspicious and wonder why they weren't underground.
The Saxon population and the refugees of York began moving into the town, ready to celebrate high mass, while thousands of Saxon troops were stationed into the town. The soldiers started cheering, relieved of the disappearance of this threat, when they were suddenly caught in the streets of York when contingents of Viking warriors, bloodthirsty and determined, started pouring out from the sewers underground that were built by the Romans and that was Ivar's plan since the beginning. Viking archers started wreaking havoc among soldiers and civilians alike, the Saxons struggling to defend themselves against the incoming tide of Viking warriors. The Saxons formed some kind of shield wall to protect their king but many were overrun and the battle emerged into a vicious, close quarter fighting. Hvitserk met Aethelwulf is close combat, both evenly matched struck blows on each other before Hvitserk was pushed away by a Saxon soldier in the chaos. While Ivar and his men progressed through the streets of York. The fight was also raging at the gates were a contingent of Saxon men formed a circle against their opponents. Heahmund took out several Vikings with master blows of his sword while Ivar's men shattered the Saxon wall by throwing spears that the Saxon took in their shields, making them stagger backwards. Heahmund then moved towards the Viking warriors, taking out a shield-maiden and making his horse crush her under his feet to impress his opponents, but his horse was brought down by archers. In the meantime, Aethelwulf, Aethelred and Alfred retreated out of the town with their men while Mannel was severely bashed in the back of the skull with a war-hammer from a ferocious Viking Berserker who then died of his wounds. Ivar, impressed by the courage and skills of the warrior bishop, interrupted the fight and told his men to give Heahmund another horse, stating that the latter was too good a warrior to fight on foot. The fight resumed but the pressure and the crushing numbers of the Vikings proved too much for the remaining Saxons, who were overrun or fled from the town. Heahmund himself was captured in the process by Ivar, shouting that he was a heathen, only to Ivar's mockery.
Following the Decisive victory the Vikings reclaim York with moderate casualties, York would then be installed with a strong garrison in place of Ivar and Hvitserk heading back to their country in seek for Ivars vengeance against Lagertha. Due to the chaotic ambush and battle Bishop Heahmund was captured and would go on to follow Ivar to Norway. The Saxon army was depleted as they broke off from York with Lord Mannel of Northumbria being a casualty of the onslaught.