They enabled Mongol nobles and officials to demand goods and services from civilian populations.
To attract foreign or overseas merchants and talents, the Great Khans gave them paiza exempting them from taxes and allowing them to use relay stations.
[2] However, Möngke Khan (r. 1251–1259) limited notorious abuses and sent imperial investigators to supervise the business of the merchants who were sponsored by the Mongols.
Marco Polo, who visited the Yuan dynasty during the reign of Kublai Khan (r. 1260–1294), left a good description of the paiza.
[4] He fashioned new paizas into two ranks, ordered that they bear the names of the bearers on them to prevent them from being transferred and required them to be relinquished at the end of the official's term.