Earliest Sundials

[Mike Cowham]

Dear Sundial Friends,     I am trying to find the earliest evidence for sundials made in Europe with gnomons aligned to the Earth's axis.  They were commonly in use after about 1550, (e.g., Nuremberg diptych dials), but I believe that there are much earlier ones.  Rohr, in his book, believes that the technology probably came to Europe from the Arabs following the crusades, the last of which finished around 1290.      One string gnomon dial is illustrated by Zinner that he believes was made by Regiomontanus in 1463.  Does anyone know of any earlier dials, fixed or portable using this 'new technology', or any dials with the new gnomon earlier than 1550?       Best Wishes to all my Sundial Friends for Christmas and the New Year. Regards, Mike Cowham Cambridge UK