Nativity Fast.
wikiwikiup Bishop Perpetuus of Tours, who died in 490, ordered fasting three days a week from the day after Saint Martin's Day (11 November). In the 6th century, local councils required fasting on all days except Saturdays and Sundays from Saint Martin's Day to Epiphany (the Feast of the Three Wise Men and the star, c.f. Matthew 2: 1-12) on January 6, a period of 56 days, but of 40 days fasting, like the fast of Lent. It was therefore called Quadragesima Sancti Martini (Saint Martin's Lent).[7] This period of fasting was later shortened and called "Advent" by the Church.en.wikipedia.org/wiki/St._Martin's_Day