Tea has more than 4000 years of history. It is one of the essentials of life in China. According to the legend, an emperor during the Neolithic period called Shennong discovered tea. In Shang dynasty (1600 - 1046 BC), tea leaves had become the royal tribute. Since the Han dynasty (202 BC - 8 AC), Chinese people started cultivating tea trees. Since the Tang dynasty (618 - 907 AC), the art of tea has become popular in China.