Chapter 1 of Volume I of "The Liturgical Year" by Dom Prosper Guéranger: The History of Advent.

Advent developed in the Western Church as a period of penitential preparation for the celebration of Christ’s Nativity, though its exact origins are difficult to pinpoint. Early evidence shows special preaching on the coming feast by the fifth century, and by the late fifth and sixth centuries various regions, especially in Gaul, observed a lengthy preparatory fast beginning around St. Martin’s day, sometimes lasting forty days and known as “St. Martin’s Lent.” Over time this discipline spread across Europe, though its rigor and length varied widely, and by the ninth century many places had reduced Advent to four weeks, with fasting gradually relaxing in subsequent centuries. While strict penitential practices eventually waned in the West, the season retained its character of spiritual preparation, and the liturgy took on a stable form of four Advent Sundays, an arrangement solidified by the early Middle Ages, though other rites, such as the Ambrosian and Mozarabic, preserved longer observances. In the East, the forty-day “St. Philip’s Fast” continues with moderate abstinence, and although its liturgy lacks a distinct Advent Office, it emphasizes expectation of the Lord’s birth through frequent allusions to the mystery of Bethlehem.Dom Prosper Guéranger's The Liturgical Year, a monumental fifteen-volume work, offers a comprehensive exploration of the Catholic Church’s liturgical calendar, guiding readers through the spiritual and historical richness of the Church’s worship. Written in the 19th century, the series provides daily meditations, historical context, and liturgical texts for the Mass and Divine Office, covering the entire cycle of seasons—Advent, Christmas, Lent, Passiontide, Easter, and the Time after Pentecost—as well as feast days of saints. Guéranger’s work, rooted in a deep contemplative spirit, aims to immerse the faithful in the Church’s prayerful life, emphasizing the unity of faith through the axiom lex orandi, lex credendi ("the law of prayer is the law of belief"), and remains a cherished resource for Catholics seeking to deepen their spiritual lives. Dom Prosper Guéranger (1805–1875) was a French Benedictine monk, liturgical scholar, and founder of the Solesmes Abbey, renowned for his pivotal role in reviving the Benedictine Order in France and restoring the Roman liturgy after the disruptions of the French Revolution. Born in Sablé-sur-Sarthe, he entered the priesthood in 1827 and, inspired by a vision to restore monastic life, reestablished the Benedictine community at Solesmes in 1833, becoming its first abbot. A staunch defender of ultramontanism and traditional Catholic worship, he also championed the revival of Gregorian chant, significantly influencing the liturgical renewal movement.Please note: The entries of the Liturgical Year are primarily authored by Dom Prosper Guéranger, but occasionally contain editors’ additions of subsequent information and events that are relevant to the given feast.Link to the Dom Guéranger's Liturgical Year playlist (updated daily, unless a Ferial day): https://www.youtube.com/playlist?list=PLZKdyYnV_bkh7rH6piW0ShgsdcefFoOvJ