Liturgical year in the context of "Revised Common Lectionary"

The Greek Orthodox Patriarchate of Jerusalem, also known as the Greek Orthodox Church of Jerusalem, is an autocephalous church within the wider communion of Eastern Orthodox Christianity. Established in the mid-fifth century as one of the oldest patriarchates in Christendom, it is headquartered in the Church of the Holy Sepulchre in Jerusalem and led by the patriarch of Jerusalem, currently Theophilos III. The patriarchate's ecclesiastical jurisdiction includes roughly 200,000 to 500,000 Orthodox Christians across the Holy Land in Palestine, Jordan and Israel.

The church traces its foundation in Jerusalem to the day of Pentecost, when the Holy Spirit, according to Christian beliefs, descended on the disciples of Jesus Christ and ushered the spread of the Gospel. The church celebrates its liturgy in the ancient Byzantine Rite – whose sacred language, Koine Greek, is the original language of the New Testament – and follows its own liturgical year under the Julian calendar.

Christian tradition is a collection of traditions consisting of practices or beliefs associated with Christianity. Many churches have traditional practices, such as particular patterns of worship or rites, that developed over time. Deviations from such patterns are sometimes considered unacceptable by followers, or are regarded as heretical. There are certain Christian traditions that are practiced throughout the liturgical year, such as praying a daily devotional during Advent, erecting a nativity scene during Christmastide, chalking the door on Epiphany Day, fasting during Lent, waving palms on Palm Sunday, eating easter eggs during Eastertide, and decorating the church in red on Pentecost.

Tradition also includes historic teaching of the recognized church authorities, such as Church Councils and ecclesiastical officials (e.g., the Pope, Patriarch of Constantinople, Archbishop of Canterbury, etc.), and includes the teaching of significant individuals like the Church Fathers, the Protestant Reformers, and the founders of denominations. Many creeds, confessions of faith, and catechisms generated by these bodies are also part of the traditions of various bodies.

Christmas is an annual festival commemorating the birth of Jesus Christ, observed primarily on December 25 as a religious and cultural celebration among billions of people around the world. A liturgical feast central to Christianity, Christmas preparation begins on the First Sunday of Advent and it is followed by Christmastide, which historically in the West lasts twelve days and culminates on Twelfth Night. Christmas Day is a public holiday in many countries, is observed religiously by a majority of Christians, as well as celebrated culturally by many non-Christians, and forms an integral part of the annual holiday season.

The traditional Christmas narrative recounted in the New Testament, known as the Nativity of Jesus, says that Jesus was born in Bethlehem, in accordance with messianic prophecies. When Joseph and Mary arrived in the city, the inn had no room, and so they were offered a stable where the Christ Child was soon born, with angels proclaiming this news to shepherds, who then spread the word.

The calendar of saints is the traditional Christian method of organizing a liturgical year by associating each day with one or more saints and referring to the day as the feast day or feast of said saint. The word "feast" in this context does not mean "a large meal, typically a celebratory one", but instead "an annual religious celebration, a day dedicated to a particular saint".

The system rose from the early Christian custom of commemorating each martyr annually on the date of their death, their birth into heaven, a date therefore referred to in Latin as the martyr's dies natalis ('day of birth'). In the Eastern Orthodox Church, a calendar of saints is called a Menologion. "Menologion" may also mean a set of icons on which saints are depicted in the order of the dates of their feasts, often made in two panels.

Halloween, also known as All Hallows' Eve, or All Saints' Eve, is a celebration observed in many countries on 31 October, the eve of the Western Christian feast of All Hallows' Day. It is at the beginning of the observance of Allhallowtide, the time in the Christian liturgical year dedicated to remembering the dead, including saints (hallows), martyrs, and all the faithful departed. In popular culture, Halloween has become a celebration of horror and is associated with the macabre and the supernatural.

One theory holds that many Halloween traditions were influenced by Celtic harvest festivals, particularly the Gaelic festival Samhain, which are believed to have pagan roots. Some theories go further and suggest that Samhain may have been Christianized as All Hallows' Day, along with its eve, by the Church. Other academics say Halloween began independently as a Christian holiday, being the vigil of All Hallows' Day. Celebrated in Ireland and Scotland for centuries, Irish and Scottish immigrants brought many Halloween customs to North America in the 19th century, and then through American influence various Halloween customs spread to other countries by the late 20th and early 21st century.

Easter, also called Pasch (/pæsk/) or Pascha (Aramaic: פַּסְחָא , paskha; Greek: πάσχα, páskha) or Resurrection Sunday, is a Christian festival and cultural holiday commemorating the resurrection of Jesus from the dead, described in the New Testament as having occurred on the third day of his burial following his crucifixion by the Romans at Calvary c. 30 AD. It is the culmination of the Passion of Jesus, preceded by Lent (or Great Lent), a 40-day period of fasting, prayer, and penance.

Easter-observing Christians commonly refer to the last week of Lent, before Easter, as Holy Week, which in Western Christianity begins on Palm Sunday (marking the entrance of Jesus in Jerusalem), includes Spy Wednesday (on which the betrayal of Jesus is mourned), and contains the days of the Easter Triduum including Maundy Thursday, commemorating the Maundy and Last Supper, as well as Good Friday, commemorating the crucifixion and death of Jesus. In Eastern Christianity, the same events are commemorated with the names of days all starting with "Holy" or "Holy and Great", and Easter itself might be called Great and Holy Pascha. In both Western and Eastern Christianity, Eastertide—also known as the Easter or Paschal season—begins on Easter Sunday and continues for seven weeks, concluding on the 50th day, Pentecost Sunday. However, in Eastern Christianity, the leavetaking of the feast occurs on the 39th day, the eve of the Feast of the Ascension.

The Coptic calendar, also called the Alexandrian calendar, is a liturgical calendar used by the farming populace in Egypt and used by the Coptic Orthodox and Coptic Catholic churches. It was used for fiscal purposes in Egypt until the adoption of the Gregorian calendar on 11 September 1875 (1st Thout 1592 AM). Like the Julian calendar (and unlike the international Gregorian calendar), the Coptic calendar has a leap year every four years invariably; it does not skip leap years three times every 400 years.

The beheading of John the Baptist, also known as the decollation of Saint John the Baptist or the beheading of the Forerunner, is a biblical event commemorated as a holy day by various Christian churches. According to the New Testament, Herod Antipas, ruler of Galilee under the Roman Empire, had imprisoned John the Baptist because he had publicly reproved Herod for divorcing his first wife and unlawfully taking his sister-in-law (his brother's wife) Herodias as his second wife. He then ordered him to be killed by beheading.

As a non-Biblical source, Jewish historian Josephus also recounts that Herod had John imprisoned and killed due to "the great influence John had over the people", which might persuade John "to raise a rebellion". Josephus also writes that many of the Jews believed that Herod's later military disaster was God's punishment for his treatment of John.