The history of candy can be traced back to 3000 years ago. The word "caramel" appeared in ancient books of Han Dynasty in China, and caramel may be the earliest hard candy. More than 1000 years ago BC, the ancient Egyptians made candy with honey, dates and figs. During the Tang Dynasty, sugarcane was introduced from India to China for planting. From the end of16th century to the middle of18th century, the French put forward crystalline sugar from beet. Europeans discovered cocoa in16th century and made it into chocolate in19th century. Candy production technology was gradually formed in the late19th century. The simple operation of boiling sugar in one pot was abandoned at the beginning of the twentieth century. Chewing gum was first introduced in the United States in the 1970s.