According to Gunther Schnabl of Leipzig University, “In the Yuan dynasty (1279–1369), Kublai Khan amazed Marco Polo with the first fiat currency (made of the bark of Mulberry trees). To ensure the purchasing power, those refusing to accept the currency as a means of payment were executed.” 

a. What is a fiat currency? 

b. Why would this currency be considered a fiat currency? 

c. Was the drastic measure Kublai Khan used to ensure that the currency circulated necessary? 

How do modern governments ensure that their fiat currencies circulate?