William was girdler and as such fashioned belts and garters out of silk, wool, leather or linen to be worn around the waist.
Belt of Fernando de la Cerda (1255-1275), Museo de Telas Medievales, Burgos
On June 17, 1376, he was accused of secretly fashioning a belt harnessed with silver. The use of precious metals like gold and silver was the privilege of a goldsmith. The trade of girdlers was allowed to use iron, steel, copper, and latone, an alloy of copper, tin, and other metals. Lead, pewter and tin were regarded as inferior substitutions and had been forbidden by ordinance in 1327.
William pleaded guilty and got away with a warning and a 40 Shilling penalty. However, the trade with fake silver articles must have been lucrative because ten years later William was caught again, this time he had made the metal tip and mouth of a scabbard out of latone and after coating them with silver, had fraudulently passed them off as the real thing.
Medieval Sword
Søren Niedziella from Denmark [CC BY 2.0 (https://creativecommons.org/licenses/by/2.0)
The Chamber of London confiscated the silvered chape and locket “to the use of the Communality” and William Bonjohn payed another fine of 40 Shillings for his offence.
Swabian Fool 