The Church contains several seasons that help to guide the worship of Catholics. The order of the year is as follows:
Advent marks the beginning of the liturgical year. We celebrate this season for four weeks leading up to Christmas. We use this season to reflect of Jesus’ coming to us in the flesh and to prepare ourselves for His coming again.
We celebrate the coming of Christ in the flesh (or the Incarnation) for a few weeks. It begins on Christmas Eve (Dec 24) and continues through a portion of January when we celebrate His baptism.
Lent takes place in the 40 days leading up to Easter. This is a season of penance and fasting, modeled to us by Jesus Himself. Before His baptism and public ministry began He retreated into the desert for 40 days of fasting and prayer. This season begins on Ash Wednesday and continues until the first Mass of the Triduum (Holy Thursday).
Holy Week (Triduum)
The Triddum (three days) leading up to Easter are the most important three days in the liturgical calendar. They begin with Holy Thursday where we celebrate the institution of the Eucharist at the Last Supper. Good Friday commemorates the passion and death of Jesus. We mark this with a solemn service and increased fasting and prayer. The Easter Vigil takes place on Holy Saturday night. It is a when new members of the Church receive the sacraments for the first time and are initiated and welcomed into the Church
The Easter season celebrates Christ’s resurrection and victory over death. We celebrate this season for around 50 days (depending on the calendar year). It ends with the celebration of Pentecost, where the Holy Spirit descended upon the apostles and they went out to spread the Gospel and the ministry of the Church to all nations.
This is the season when we reflect upon the mission Jesus has given to us all. We reflect upon His teachings and example and pray that we may enter into that mission to share the gospel. We celebrate many various feasts throughout this time. Ordinary time ends with the Solemnity of Christ the King which ends the liturgical year and sends us into Advent.
During the year, in addition to the obligatory Sunday worship, the Church also celebrates Solemnities, Feasts and Memorials which may be on any day of the week. Some of these are considered Holy Days of Obligation where all Catholics are obliged to come together to celebrate Mass. Others are days that commemorate special events or persons that are highly revered in the tradition and history of the Church.