Vespers: Orthodox Service Books - Number 6

In the Eastern Orthodox Church and those Eastern Catholic Churches which follow the Byzantine Rite, there are three forms of Vespers: Great Vespers, Daily Vespers and Small Vespers. Great Vespers is the form served on Sundays and major feast days when it may be celebrated alone or as part of an All-Night Vigil, or as the commencement of the Divine Liturgy, or on a few special occasions, e.g., Good Friday or Pascha afternoon. Daily Vespers is the form served on other days when Great Vespers is not served. Since the liturgical day begins at sunset, Vespers is the first service of the day, and the hymns of Vespers introduce the themes of the upcoming day.