Rogation days are, in the calendar of the Western Church, four days traditionally set apart for solemn processions to invoke God's mercy. They are April 25, the Major Rogation, coinciding with St. Mark's Day (but having no connection with it); and the three days preceding Ascension Day, the Minor Rogations.
The first Rogation, the Greater Litanies, was introduced as a Christian substitute for the Roman pagan celebration Robigalia, which was a special celebration to pray for crops. This day is observed on April 25. If Easter falls on this day, the latest possible date for Easter, the Rogations are transferred to Tuesday, April 27.
The second set of Rogation days, the Lesser Litanies or Rogations, introduced about AD 470 by Bishop Mamertus of Vienne and eventually adopted elsewhere, are the three days (Rogation Monday, Rogation Tuesday and Rogation Wednesday) immediately before Ascension Thursday in the Christian liturgical calendar. The term, most frequently encountered in Roman Catholic and Anglican circles, is rarely used today.
The word "Rogation" comes from the Latin verb rogare, meaning "to ask," and was applied to this time of the liturgical year because the Gospel reading for the previous Sunday included the passage "Ask and ye shall receive" (Gospel of John 16:24). The Sunday itself was often called Rogation Sunday as a result, and marked the start of a three-week period (ending on Trinity Sunday), when Roman Catholic and Anglican clergy did not solemnize marriages (two other such periods of marital prohibition also formerly existed, one beginning on the first Sunday in Advent and continuing through the Octave of Epiphany, or 13 January, and the other running from Septuagesima until the Octave of Easter, the Sunday after Easter).
The faithful typically observed the Rogation days by fasting in preparation to celebrate the Ascension, and farmers often had their crops blessed by a priest at this time, which always occurs during the spring in the Northern Hemisphere. Violet vestments are worn at the rogation litany and its associated Mass, regardless of what colour was worn at the ordinary liturgies of the day. A common feature of Rogation days in former times was the ceremony of "beating the bounds", in which a procession of parishioners, led by the minister, churchwarden, and choirboys, would proceed around the boundary of their parish and pray for its protection in the forthcoming year.
The Roman Catholic calendar reforms of 1969 officially eliminated the Rogation days from the church calendar, and the Sunday preceding Ascension Thursday is now known simply as the Sixth Sunday of Easter. This observance in the Catholic Church has revived since 1988 (when Pope John Paul II issued his decree Ecclesia Dei Adflicta) and especially since 2007 (when Pope Benedict XVI issued his motu proprio called Summorum Pontificum) when use of such older rites has again been permitted and encouraged. Churches of the Anglican Communion reformed their liturgical calendar in 1976, but continue to recognize the three days before Ascension as an optional observance.