Nuremberg in Bavaria was a great centre of trade in the 15th and particularly 16th century, between Italy and the east, and also between northern and southern Europe. It also accommodated an outstanding range of workshops in metalwork and other specialist crafts. These circumstances favoured the growth of one of the most important centres of instrument making in the medieval and renaissance period. Other, more personal, factors were the influence of the astronomer Joannes Regiomontanus, who settled there in 1472 and established a workshop and printing house, and the success of the talented and prolific maker Georg Hartmann. Another cartographer and instrument maker, Erhard Etzlaub, was one of the first to produce that characteristic instrument of the Nuremberg trade, the ivory diptych dial: through the 16th and 17th centuries they were made in great numbers within a series of families specialising in this type of sundial.
