Detailed Instructions: In this task you will be given an answer to a question. You need to generate a question. The answer given should be a correct answer for the generated question.
Q: A Christmas tree is a decorated tree, usually an evergreen conifer such as spruce, pine, or fir or an artificial tree of similar appearance, associated with the celebration of Christmas. The modern Christmas tree was developed in medieval Livonia (present-day Estonia and Latvia) and early modern Germany, where devout Christians brought decorated trees into their homes. It acquired popularity beyond the Lutheran areas of Germany and the Baltic countries during the second half of the 19th century, at first among the upper classes.
A:
when did decorations on the christmas tree began