The history of Anglo-Saxon London relates to the history of the city of London during the Anglo-Saxon period, during the 7th to 11th centuries.
Romano-British Londinium had been abandoned in the late 5th century, although the London Wall remained intact. There was an Anglo-Saxon settlement by the early 7th century, called Lundenwic, about one mile away from Londinium. Lundenwic came under direct Mercian control in about 670. After the death of Offa of Mercia in 796, it was disputed between Mercia and Wessex.
Viking invasions became frequent from the 830s, and a Viking army is believed to have camped in the old Roman walls during the winter of 871. Alfred the Great re-established English control of London in 886, and renewed its fortifications. The old Roman walls were repaired and the defensive ditch was re-cut, and the city now became known as Lundenburh, marking the beginning of the history of the City of London. Sweyn Forkbeard attacked London unsuccessfully in 996 and 1013, but his son Cnut the Great finally gained control of London, and all of England, in 1016.
Edward the Confessor, the step-son of Cnut, became king in 1042. He built Westminster Abbey, the first Norman Romanesque church in England, consecrated in 1065. Edward's death led to a succession crisis, and ultimately the Norman invasion of England.
More information on the Wikipedia page [1]: there is much other coverage, including the Museum of London page [2].