This is one of the last recorded instruments by the famous Nuremberg maker Georg Hartmann who died in 1564. The diptych dial is stamped with the Nurembergdial maker Hieronymus Reinmann's mark, a crown. Many of Reinmann'sdials show close similarity with Hartmann'sdials and it is therefore likely that Hartmann, who was never a member of the compass maker's craft himself, commissioned compass makers such as Reinmann to produce diptych dials according to the technical designs which he produced himself.