In 1443, as the foundations for the north tower are being dug, a sensation comes to light: a huge thigh bone, thought to be the remains of a giant man who is supposed to have aided in the building of the original church. The bone is immediately hung up over the main entrance, which, according to tradition, is subsequently known as the giant’s door. In actual fact the find is the bone of a mammoth and today resides in the Geological Institute at the University of Vienna. Inscribed on one side is the date 1443; on the other Holy Roman Emperor Frederick III’s famous and as yet to be decoded motto, “AEIOU”.
So much for legend. It’s more probable that the name ‘giant’s door’ - in German “Riesentor” – comes from the Middle High German word “risen”, which means to fall, and refers to the funnel-shaped, tapered portal, bordered by 7 columns on each side.