Saint Mary-le-Bow marks the position of an original Saxon church believed to date from the late 700s.
The bells of the church were used as curfew bells and could be heard all over the city. Anyone born within the sound of the Saint Mary-le-Bow bells is said to be a 'true' cockney.
The twelfth century building was destroyed in The Great Fire and rebuilt by Wren by 1680.
Saint Mary-le-Bow was destroyed during the bombing of 1941 and finally restored in 1964.
More information can be found on Wikipedia and from Saint Mary's website.