Earl Aethelred of Mercia

Earl Æthelred, of Mercia, was given control of London in 886 AD by King Alfred who was his brother-in-law.

As Alfred reconquered the Danelaw, it was useful to place the heir to the destroyed Kingdom of Mercia in control of his former area - it allowed the expansion of the Kingdom of Wessex to appear as a liberation of area conquered by the Danes.

For context read Lundenwic, Lundenburgh and MOLAS