The history of Chinese paper money is vast and includes the earliest known paper money usage. Merchants began using promissory notes (or exchange notes) during the Tang Dynasty (618-907). The Song Dynasty (960-1279) issued what is considered the world’s first generally circulating paper currency called Jiaozi. For collectors, China’s more recent banknotes of the 19th and 20th centuries span multiple governmental eras, from the Qing Dynasty to the People’s Republic offering tremendous variety and areas for specialization, including the issues of domestic and foreign banks, regional issues, emergency issues and more.