The liturgical year consists of a regulated order of special seasons and feasts in the Church, designed particularly to commemorate important events in the life of Christ.
The Catholic Church arranged the principle religious observances according to a definite order of time. This was done not only by following the civil arrangement of the year, but according to a calendar of its own. According to the ecclesiastical arrangement, the liturgical year is centered on Easter.
Unlike the civil year, divided into days, months, and seasons, the liturgical year is divided into weeks, linked together into special periods of time which compose the cycles. The most important cycle, the the first in chronological and historical formation, is the Psychal cycle, commemorating the feast of the Resurrection or Easter. This is followed by fifty festive days after Easter; the Ascension is the fortieth day after Easter. A forty-day period of preparation for Easter is called Lent; this is divided into the four Sundays of Lent, First Passion Sunday and Second Passion Sunday (Palm Sunday), which opens Holy Week, the commemoration of the Passion and Death of Christ.
A second cycle, which parallels in composition for the Easter cycle, is the Nativity, commemorating the birth of Christ—December 25. A four-week period of preparation precedes this feast, called Advent, which recalls the long period of expectation of a Savior by the Jewish people. The Nativity is followed by a period of joyful celebration, comprised of the Sunday after the Nativity, the Epiphany, and an undetermined number of Sundays after the Epiphany, which number six at the most. Next occurs a transition period before Lent, called Septuagesima (seventy days), Sexagesima (sixty days), based on the number of days preceding Easter.
The period of time following the feast of Pentecost constitutes a section called the Season after Pentecost, consisting of 24 Sundays, to which are added, as occasion demands, the remaining Sundays after the Epiphany. This post-Pentecostal period forms a connecting link with Advent and hence, with the beginning of a new liturgical year. Within this, the feast of Corpus Christi is celebrated on the second Thursday after Pentecost.
To these feasts of the Lord were added other minor ones commemorating phases of His life—the Transfiguration, the Sacred Heart, and the Holy Name of Jesus.
In addition, feasts commemorating His Blessed Mother were inserted in the calendar—the Assumption, the Immaculate Conception, and the Annunciation of the Incarnation of the Word, along with other minor feasts.
The saints also occupy a large part of the liturgical year—All Saints Day, All Souls Day, and feasts in honor of individual saints. The Sanctorale or commemoration of the saints follows the civil calendar, while the Temporale follows the Easter cycle with movable feasts.
