Before the arrival of Christianity, Germanic and Scandinavian peoples lit candles using wreaths during the dark and cold winter days as a sign of hope in the future warm and sunlit days of spring. By the Middle Ages, Christians adapted this tradition and used "Advent Wreaths" as part of their preparation for Christmas. After all, Christ is "the Light that came into the world" to dispel the darkness of sin and radiate the love of God (cf. John 3:19-21).
The evergreens of the wreath signify undying life. The circle symbolizes the eternity of God. The four candles represent the four weeks of Advent. The three purple candles signify our prayer, penance, and charitable works. The one rose candle represents the joy we are called to embrace as we await the arrival of Christmas. The progressive lighting of candles bespeaks our hope as we anticipate the celebration of Christ's birth as well as Christ's coming at the end of time when his victorious light will conquer ever darkness.
This ancient tradition, during the darkest season of the year, reminds us that the light of Christ transforms the darkness in our hearts and of our world. Transformed by the light Christ, each of us brings light to others in his or her unique way.