 It is "impossible to claim with confidence a credible explanation of the origin of Advent".Associated with Advent was a period of fasting, known also as the Nativity Fast or the Fast of December.According to Saint Gregory of Tours the celebration of Advent began in the fifth century when the Bishop Perpetuus directed that starting with the feast of St. Martin, 11 November, until Christmas, one fasts three times per week; this is why Advent is also named Lent of St. Martin.