The Christmas tree tradition is believed to have originated in Germany during the Middle Ages. It is thought that the first Christmas trees were decorated with edible items such as apples, nuts, and berries, as well as candles. The tradition of decorating a tree with candles was later popularized by Martin Luther in the 16th century, who was inspired by the beauty of the starry sky. The tradition of using a Christmas tree as a decoration then spread to other countries, including the United States, where it became a popular tradition in the 19th century.