Before the introduction of regular mail service by governments, letters and messages had to be transported by heralds and trusted messengers employed by feudal lords or city magistrates. These men were identified on their official missions by shield-shaped badges worn on their clothing and displaying the heraldic arms of their employers. In some early examples, these badges were constructed as boxes with lids, probably to store credentials or even small messages on parchment. Many of the badges were made of silver and were often decorated with enamel.