On this page of Assassin's Creed Valhalla's game guide, you will find a detailed description of The Thegn of Lincoln mission.
Since Aelfgar was indicated as a candidate to replace the late Hundbeorth, Eivor goes to the Thegn to get to know him a little better.
Reward: 1,700 XP.
- Talk to Aelfgar (Speak to Aelfgar)
- Follow Aelfgar
- Search for the bear inside of the cave
- Reach the Aelfgar's Estate
Talk to Aelfgar (Speak to Aelfgar)
Go to Aelfgarstun to speak with the local Thegn. Interestingly, Aelfgar offers Eivor a bow, which previously belonged to Hunbeorth, and invites him to hunt.
Aelfgar's manor is devastated for weeks by a big bear, so he wants to hunt this beast. Get on your horse and follow the Thegn.
At the place where the hunt is to take place, you will meet Grim, a Norman warrior who came there at the explicit request of Aelfgar.
Search for the bear inside of the cave
Go to the bear's den. Once you enter the spacious cavern you might be attacked by a pack of wolves.
Exit the cave to join Grima. From the hilltop, you will notice that Aelfgar's estate is on fire.
Reach the Aelfgar's Estate
Once you're there, you will encounter Mercian soldiers burning and plundering the settlement of Aelfgarstun. Defeat all invaders.
After the fight, talk to Aelfgar. After a short cut-scene the mission will end. As a reward, you will receive 3,400 XP.