Joseon officials who had to travel great distances on official business would carry a badge called a “mapae,” which allowed them to requisition horses. The number of horses on the front of the badge corresponds to the number of horses that the official could requisition, depending on his rank. The back of each badge was inscribed with the date of issue, a serial number, and the name of the office that issued the badges: Sangseowon, the Office of Royal Seals and Insignia. These badges were initially made from wood, but the wood badges were too susceptible to damage. Thus, starting in 1434 under King Sejong, the badges began to be made from iron. Then around 1485, with the promulgation of Gyeongguk Daejeon (Complete Code of National Governance), the badges began to be made from copper.