A year later, in 886, Alfred reoccupied the city of London and set out to make it habitable again. Alfred entrusted the city to the care of his son-in-law Æthelred, ealdorman of Mercia. The restoration of London progressed through the latter half of the 880s and is believed to have revolved around a new street plan; added fortifications in addition to the existing Roman walls; and, some believe, the construction of matching fortifications on the south bank of the River Thames.