The Christian Year
The early Christians who were mainly Jews were used not only to keeping one day in the week as separate but also to marking the year with certain religious festivals, notably Passover, Tabernacles, and Pentecost. From early times Christians kept a commemoration of Christ's resurrection. This was held at Passover time and was finally fixed on the Sunday following Passover. Pentecost was then celebrated at the appropriate time; the fifty days between the two were days of joy and rejoicing. The choice of 25 December (in the East, 6 January) for the birth of Christ is almost certainly because that day was the great pagan day of honor to the sun, and in Rome in the fourth century it was transformed into a Christian festival.
From the fourth century the Christian calendar became more historical in character, and Holy Week and Ascension Day appeared. Pentecost became the day of the giving of the. Lent arose out of the custom of preparing catechumens for baptism at Easter. Saints' days came into the calendar either through the commemoration of a martyrdom or through the date of a dedication of a church in honor of a particular saint. The advantage of the Christian Year is that through the church services, and in particular the choice of Scripture passages to be read, worshipers are regularly reminded of the great events of the Christian faith and a balance is kept between them. In recent years there have been various suggestions for modification of the calendar, particularly in relation to Advent and Lent, and some demand, supported by secular sources, for a fixed date for Easter.