The time of the Tang brought an innovation to coinage: Gaozu (618-627), the first of the Tang emperors, introduced the ch'ien, the coin that would later be known as "cash" in the West. Gaozu began to indicate his "nian hao" on his coins – the motto that each Chinese emperor had for his reign. For the Chinese the nian hao not only described the motto of an emperor's reign, but the emperor himself, since it was forbidden to speak out his name.