A number of churches in and around the City of London later came to dedicated to St Olaf.
This is because, in 1014, Olaf Haraldsson, as he then was, was an ally of the Saxon English, under Ethelred “The Unready”, in their fight against the against the Viking Danish, under Cnut, and he helped save Saxon London from Viking attack (albeit only temporarily).
According to the Norse Sagas, he destroyed the Saxon incarnation of London Bridge, and the Viking army assembled on it poised to attack, by pulling it down with ropes tied to his long-boats.
The court poet Ottar Svarte wrote, in the eleventh century, and Snorri Sturluson rewrote, in the thirteenth:
“London Bridge is broken down.
Gold is won, and bright renown.
Shields resounding, war-horns sounding,
Hild is shouting in the din!
Arrows singing, mail-coats ringing-
Odin makes our Olaf win!”.
Many believe this to be the origin of the much-loved nursery-rhyme “London Bridge is falling down”.