signet rings were introduced for two reasons: 1) make sure any tampering with the content is visible 2) people were mostly illiterates at the time so it made se

signet rings were introduced for two reasons: 1) make sure any tampering with the content is visible 2) people were mostly illiterates at the time so it made sense for them to have something else than signing with XXX My guess is that as illiteracy in Europe decreased the need for signet rings also decreased