What was an accomplishment by the tang dynasty of china?
the tang rulers created the first paper currency in history.
the tang rulers defeated kublai khan after a long war.
the tang rulers expanded into the mongol empire.
the tang rulers established a system of coinage.

The Tang rulers established a system of coinage. This was an accomplishment by the Tang Dynasty of China.

The system of coinage began in Tang dynasty and continued its existence in the succeeding dynasties.

Kai Yuan Tong Bao was written in character on the coin currency circulated all throughout China beginning on the Tang dynasty. Kai Yuan Tong Bao's size, weight and the accordance of name with the form made it not only the main currency of the Tang Dynasty but also the norm of the coin in the next dynasties.

Since it was minted during the Tang dynasty, it was used without discontinuity. Its usage even extended to the collapse of the Tang dynasty. This form of money was used for 1300 years before replaced by Hong Xian Tong Bao.