These silver badges were struck for sewing on to the coats of the 40 mathematical scholars of the mathematical school established within Christ's Hospital School (the Bluecoat school) in 1672 by Charles II. Its purpose was to improve practical navigation skills. This one is perforated round the rim with eight holes for sewing on and has seen much use. See MEC0879, which is a mint-condition unperforated example, for description. The design is a variation of the reverse of the foundation medal of the mathematical school, also by Roettier. It is assumed they were struck in batches, the early ones being silver but none being hall-marked. They are therefore not precisely dateable except to say that at some point in the mid-18th century, when it was found that boys were selling them for their silver value, they were replaced with the same design in silver plate. [PvdM 3/06]