Nayan (Mongol Prince) 'Prince of Kwang-ning'. In addition, Nayan was also the foremost leader of the Eastern "ulus"es (tribal groupings and districts ruled by Mongol appanage princes) dominated by the descendants of the brothers of Genghis Khan. Whatever the precise extent of Nayan's appanage, he certainly held sufficient lands within and around Manchuria to give him a power-base from which to launch a rebellion against his kinsman Kublai Khan. Nayan is represented as embodying a traditional Mongol reaction against the increasing sinicisation shown by Kublai Khan and his administration. Nayan adhered to the ancestral nomadic values of the Mongols and was dismayed at
Society of the Mongol Empire when the Song dynasty started replacing their copper coinage with paper currency. When the Mongols invaded Song China they started issuing their own Mongolian bills in 1227. This first attempt by the Mongols did not last long because the notes issued expired after several years and were inconsistent throughout the parts of the Mongol Empire that issued them. In 1260, Kublai Khan created the Yuan Mongol's first unified paper currency with notes that did not have any expiration date. To validate the currency, it was made fully exchangeable to silver and gold and was accepted as tax payments. Currency distribution