Originally the feast of Pentecost brought to an end in Rome the fifty days of the Easter celebrations and introduced the fast of the Ember Days of the summer quarter. Afterward, it became customary to continue the festivity for two more days, the Monday and the Tuesday, and, finally, after the time of Pope St. Leo the Great, it was extended like the Octave of Easter through the entire week. For many centuries, Pentecost Monday and Pentecost Tuesday were Holy Days of Obligation.
The fasting and abstinence on the Ember Days of Pentecost is unique in the Church as these are the only Ember Days celebrated without violet vestments. But the Ember Days of Pentecost are meant to be a joyful fast.
In medieval times, families in many parts of Europe would suspend a carved and painted wooden dove over their dining table during this time of Pentecost. Such a custom could be easily revived for the throughout the Octave of the Pentecost -- and imagine that dining room table covered with a white tablecloth, sprinkled with red rose petals.
Dom Guéranger, O.S.B. in The Liturgical Year insightfully writes: "The Christian Pentecost, prefigured by the ancient one of the Jews, is of the number of the feasts that were instituted by the apostles. As we have already remarked, it formerly shared with Easter the honour of the solemn administration of Baptism. Its octave, like that of Easter, and for the same reason, ended with the Saturday following the feast. The catechumens received Baptism on the night between Saturday and Sunday. So that the Pentecost Solemnity began on the vigil, for the Neophytes at once put on their white garments: on the eighth day, the Saturday, they laid them aside."
There is a profound connection of the Scripture readings at Mass during the Octave of Pentecost with each of the Sacraments. And the Stational Churches of the Octave of Pentecost have a unique connection to the stations during the Octave of Easter.
Up until 1955 but after the time of Pope St. Pius X, Octaves were arranged in the following hierarchical order:
- Privileged Octaves
- Privileged Octaves of the First Order
- Octave of Easter
- Octave of Pentecost (Notice it's rank in the utmost category!)
- Privileged Octaves of the Second Order
- Octave of Epiphany
- Octave of Corpus Christi
- Privileged Octaves of the Third Order
- Octave of Christmas
- Octave of the Ascension
- Octave of the Sacred Heart
- Privileged Octaves of the First Order
- Common Octaves
- Octave of the Immaculate Conception of the BVM
- Octave of the Solemnity of St. Joseph
- Octave of the Nativity of St. John the Baptist
- Octave of Saints Peter and Paul
- Octave of All Saints
- Octave of the Assumption of the BVM
- Simple Octaves
- Octave of St. Stephen
- Octave of St. John the Apostle
- Octave of the Holy Innocents
Sadly, Paul VI abolished the Octave in 1969, although he did not even realize it when he signed the authorization, in one sad example of his lack of oversight. Thankfully, Traditional Catholic priests keep this Octave. And even some priests who say the Novus Ordo Mass choose to celebrate Votive Masses in Honor of the Holy Ghost over this week.