Salisbury Cathedral celebrates the beginning of Advent with a candle lit service and procession, "From Darkness to Light," in Salisbury, Britain Nov. 27, 2015. REUTERS/Peter Nicholls

The traditional Advent period, which begins on the fourth Sunday before Christmas Day, began this year on Nov. 27 and will last through Christmas Eve. It is a period celebrated by Roman Catholics in preparation for the coming of Christ.

The traditional celebration of Advent includes praying and fasting — not eating meat on Fridays and not snacking between meals. Advent, which comes from the Latin word for “arrival” — adventus — is also observed by certain Protestant churches.

On Wednesday, the Archbishop of Armagh Eamon Martin launched a specially commissioned online Advent calendar.

"It is a time of waiting, conversion and hope. Advent also prepares us for the second coming of Christ at the end of time. As Christians, we must always be prepared for the coming of the Lord," he reportedly said. "Preparation does not happen at once but over time and so each day of Advent amounts to a period of time which allows us to journey and reflect on the joy of the Gospel. Our online calendar is a helpful resource in this journey."

To view the online Advent calendar, click here.

Here are some important facts about the beginning of the Christian Christmas season.

  1. Many assume that Dec. 1 is the start of the Advent season. However, Advent begins on the fourth Sunday before Christmas Day. This year, the four Sundays of Advent are Nov. 27 (First Sunday of Advent), Dec. 4 (Second Sunday of Advent), Dec. 11 (Third Sunday of Advent), and Dec. 18 (Fourth Sunday of Advent).
  2. Advent Wreath is a standard symbol and includes four candles — three purple and one pink — in a circle around branches of yew, holly or another evergreen. When lit, the candles are supposed to symbolize the light of Christ.
  3. The first known mention of Advent is found in the books making up the "History of the Franks."
  4. The themes of Advent are hope, peace, joy and love.
  5. The most famous hymn of Advent is "O Come Emmanuel."