About Advent wreaths:
Advent wreaths have their origins in the folk traditions of northern Europe, where in the deep of winter people lit candles on wheel-shaped bundles of evergreen. Both the evergreen and the circular shape symbolized ongoing life. The candlelight gave comfort at this darkest time of the year, as people looked forward to the longer days of spring.
Later, Eastern European Christians adopted this practice. By the sixteenth century, they were making Advent wreaths much as we know them today. An advent wreath traditionally contains four candles-three purple and one rose. Purple dyes were once so rare and costly that they were associated only with royalty; the Roman Catholic Church and the Anglican and Episcopal Churches have long used this color around Christmas and Easter to honor Jesus. The three purple candles in the Advent wreath symbolize hope, peace, and love. These candles are lit on the first, second, and fourth Sundays of Advent. The rose candle, which symbolizes joy, is usually lit on the third Sunday.
Sometimes a fifth candle is placed inside the Advent wreath. This candle is lit on Christmas Day. It is white, the color associated with angels and the birth of Jesus.
Because Advent wreaths are an informal celebration, not all are the same. Instead of purple candles, some people use blue, which recalls the color of the night sky before daylight returns. Others use all white candles.
Information gathered by Jon Elvrum