15th November until 24th December.
The birth of Jesus is normally celebrated on 25th December, but most scholars agree that it is unlikely he was actually born on this date. It is more likely that the church decided to celebrate on this date to ensure that less people would attend pagan solstice festivals falling on the same day.
The term Advent means the arrival of something momentous that has been awaited. This is the time of the year when the church requires followers to prepare for the anniversary of the birth of Jesus Christ.
In the year 567 AD the second Council of Tours required monks to fast from the beginning of December until Christmas. Over time this period extended to 40 days and to all believers, ending at Christmas.
In the ninth century the Advent fast was again reduced to four weeks by Pope Nicholas I. In the year 1281 the Council of Salisbury decided that only monks needed to fast.
During Advent people abstain from meat, butter, milk and eggs, but they are allowed fish, oil and wine. People are only required for seven days out of the forty days before Christmas.