The Wiener Neustadt Altar
A.E.I.O.U.
In 1437, while still a duke, Frederick starts using the order of vowels (AEIOU) as a signature on his possessions. Conrad of Grünenberg, a contemporary of Frederick, explains in his book of heraldry that the five vowels are an acronym for ‘all er(d) ist osterreich unttertan…all ere ist ob unns’ (all the world is subordinate to Austria).
