In Malory this can be read:
So in the greatest church of London, whether were Paul's or not the French book maketh no mention, all the estates were long or day in the church for to pray [for the choice of a king].
“Paul’s” would of course be old St. Paul’s Cathedral.
See also
London | The Legend of King Arthur
London Bridge | The Legend of King Arthur
Tower of London | The Legend of King Arthur
Source
Le Morte Darthur | Sir Thomas Malory, 1469-1470