Polyhedral sundial

Object name: Polyhedral sundial

Materials and size: Gilt brass; 100 mm in height

Creation: Attributed to Nicolaus Kratzer and commissioned by Cardinal Wolsey. Probably made in London or Oxford, 1518-1530

Museum of the History of Science, University of Oxford, Oxford, UK

EMu user since 2006



februaryThe polyhedral sundial was an exercise in Renaissance mathematical virtuosity. The challenge in their design is to set a separate dial on each face of the chosen solid so that every face receiving the sun tells the time. In this case the shape is based on an octagon and accommodates nine sundials.

Although the instrument is unsigned, it was probably made by the German mathematician Nicolaus Kratzer, who came to England in about 1518 and was astronomer to Henry VIII. Kratzer became a member of Corpus Christi College, Oxford, where he read the mathematical lecture founded by Cardinal Wolsey, Archbishop of York. This instrument was made for Wolsey; the four-sided base has Wolsey's arms, the arms of York Minster, and (on two sides) a cardinal's hat. It must date from before 1530, the year of Wolsey's political downfall and death.

The arrival of Kratzer in England brought a new level of skill and mathematical ambition to the courtly circles around Henry VIII. Kratzer repeatedly collaborated with another "stranger" at Henry's court, Hans Holbein, and he sat for a portrait by him. The portrait shows Kratzer as an instrument maker at work on another polyhedral dial, and his instruments also appear prominently in Holbein's celebrated painting of "The Ambassadors". 

By permission of the Museum of the History of Science, University of Oxford.