how did red and green become christmas colors

Well, that's a great question! The use of red and green as Christmas colors actually dates back to the early 17th century when Europeans began using these colors to represent the holiday season. Red has long been associated with the color of blood and thus, with the sacrifice of Christ on the cross. Green, on the other hand, has long been associated with nature and the season of winter, when trees are barren and the landscape is bleak. So, by combining these two colors, the holiday season was associated with the themes of sacrifice, life, and rebirth.