Built 1686-1707 ; the building was designed by Wren to be supported around its perimeter by stone columns but the borough Council demanded that Wren should insert additional columns within the covered area, in order to support the weight of the heavy building above; Wren was adamant that these were not necessary. The council insisted and the extra supporting columns were built, but Wren made them slightly short, so that they do not quite touch the ceiling, proving his claim that they are not necessary