Anglo-Saxon London

   We left London in ruins, during its so-called Dark Ages. But the city's location on Thames was too good for that decline to last any longer. And eventually in 7th century London grew once more, stronger and greater than it was before. It didn't mean the end of London's problems of course.
  After Dark Ages Saxons moved in to London. They built a new settlement which they called "Lundewic"   (in Old English it was a name of a trading town). For archeologists' suprise traces of that early Saxon period were found not where the Roman Londinium was located, but much further on the west. 
  London developed and was becoming wealthier and much more attractive for foreign tribes. In 9th century Danish Vikings sailed to the river Thames and from 830 they attacked London regulary.

  The one who kicked off the Danes from British lands ,was Alfred the Great in 886. He made London a part of his kingdom called Wessex but after his death London was again in hands of Danish vikings. During Danish occupation London was attacked by Anglo-Saxons and Norwegian vikings. These attacks stopped when the Dunish king Knut managed to unite Anglo Saxons with Danes. After his death Edward the Confessor came into power of London.

(1st picture - Edward the Confessor, 2nd picture - William the Conqueror)

  After death of Edward the Confessor the new king was crowned in the abbey in Westminister - it was William the Conqueror.

London was now the most prosperous and largest citity in the British island, however it wasn't the capital...

...yet. Although everybody knew that it wasn't just a normal city. It was meant to be something greater.

Sources:

http://www.britainexpress.com/London/anglo-saxon-london.htm

http://www.history.co.uk/study-topics/history-of-london/from-anglo-saxons-to-a-norman-invasion