People put stars on top of Christmas trees to symbolize the Star of Bethlehem. This star announced the birth of Jesus to the Wise Men.
Decorated Christmas trees date back to 1510 in Latvia, according to The Christmas Archives. Later, German friar, Martin Luther, is said to be one of the first to use lights on trees by adding candles to give his children an idea of how stars twinkle through the night.
German Christmas trees originally featured edible decorations, such as gold-covered fruit and gingerbread, and tree toppers were a figure of baby Jesus. This later became an angel or star, which both have biblical connotations. The angel symbolizes the archangel Gabriel, who told Mary about the birth of Jesus. People add stars to symbolize the Star of Bethlehem, which heralded Jesus's birth and led the Magi, or Three Wise Men, to Bethlehem.
The tradition of Christmas trees arrived in the United States in the 1700s with German soldiers bringing their customs to the country. The first Christmas tree to appear at the White House was in 1856 during the presidency of Franklin Pierce, as stated by the University of Illinois. In 1979, the star on top of the National Christmas Tree was the only lit ornament.