Saint Margaret Mary Alacoque (1647–1690) was a French Visitation nun and mystic best known for her visions of the Sacred Heart of Jesus, through which she spread devotion to Christ’s divine love and mercy. Born in Burgundy, she experienced deep piety from childhood and consecrated herself to God at a young age after recovering from a severe illness. Entering the Visitation convent at Paray-le-Monial, she received a series of revelations between 1673 and 1675 in which Christ showed her His Heart burning with love for humanity and asked her to promote its veneration through the First Fridays devotion, Holy Hours, and the Feast of the Sacred Heart. Despite opposition and skepticism, her confessor, Saint Claude de la Colombière, supported her mission, and devotion to the Sacred Heart eventually spread worldwide. She died in humble obedience and holiness, and was canonized by Pope Benedict XV in 1920.

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.