Agreed with @erafjel - to follow up, they were distributed to participants, with a few gold pieces struck for the king, Royal cabinet, etc., a greater number of silver pieces for higher ranking participants, and copper examples issued to lower ranking officials / entourage.
Although they were in reality souvenirs, jettons fulfilled a function in the highly complex accounting system that emerged in the 13th century, and was in use in various forms until the early 19thc. Basically they were moved around in a specially designed cabinet to track various accounts simultaneously. The best account of this system that I have been able to find is in the 'Handbook of Medieval Exchange' by Spufford, in which it gets its own chapter.
Although they were in reality souvenirs, jettons fulfilled a function in the highly complex accounting system that emerged in the 13th century, and was in use in various forms until the early 19thc. Basically they were moved around in a specially designed cabinet to track various accounts simultaneously. The best account of this system that I have been able to find is in the 'Handbook of Medieval Exchange' by Spufford, in which it gets its own chapter.






















