The chancellor (Chinese: , zaixiàng; , chéngxiàng) – also translated chief councillor and prime minister – was the highest-ranking official in the imperial government in ancient China. The chancellor can also refer to a specific post in the imperial government, which was first officially instituted in Qin dynasty (221–206 BC) as the "head of all civil service officials". The term was known by many different names throughout Chinese history, and the exact extent of the powers associated with the position fluctuated greatly even during a particular dynasty.