 A consular diptych was commissioned by a "consul ordinarius" to mark his entry to that post, and was distributed as a commemorative reward to those who had supported his candidature or might support him in future.From as early as the first century CE, some formal letters of appointment to office were known as "codicilli", little books, two or more flat pieces of (usually) wood, joined by clasps, lined with wax on which was written the letter of appointment.Later, the letter might be written on papyrus and presented within the covers.