Advent is the first season of the Christian year . It begins four sundays before Christmas which is always December 25 to coincide with the Sol Invictus , the pagan feast to the birth of the Unconquered Sun . I is attributed to starting this tradition to symbolize the birth of God's Son . The first known reference to this custom was found in a 4th century calendar .
Advent is a time to spiritually prepare for the birth of Jesus .
The four candles stand for the four weeks of Advent . They are purple to symbolize penance and prayer , although the third one may be rose for rejoicing on Gaudete Sunday , and they all may be replaced with white on Christmas eve or a fifth candle can remain in the middle to light on Christmas eve and day . The candles are to be a perfect light to burn away the darkness of man's sin by the radiance of the Emmanuel's Love . The ritual at home may involve prayer , readings , and song before lighting the candles . This is usually started before dinner after mass on Sunday and continued through the week , lighting one candle for each week of Advent .