The feast of All Saints’ Day dates all the way back to the very first centuries of the Church. Blessed Ildefonso Schuster, OSB (1880-1954), Cardinal-Archbishop of Milan, known for his works on the liturgy, gives the following outline of the origins of this feast.
As a collective feast of all the blessed in Heaven, All Saints’ Day has very ancient precedents in various liturgies, especially the oriental liturgies.
The Sacramentaries – that reveal the liturgy used in the Church of Rome – from before the 9th century make no mention of this feast, for Rome only welcomed it around this time.
A collective feast of all the martyrs, in relation with the Easter triumph of the Redeemer, first appeared in Syria during the 4th century. The Byzantine Catholics celebrated it on the Sunday after Pentecost, a custom that was also adopted in Rome, as can be seen in the most ancient Comes – or lectionary of the Roman Church – published by Dom Morin according to the famous Würzburg manuscript: Dominica in natale Sanctorum, “the Sunday celebrating the birth of all the saints in Heaven”.
This feast, however, was only transplanted from Byzantium to the banks of the Tiber for a short time, and here is why: during the week after Pentecost, an ancient tradition imposed the solemn Ember Day fast on the Romans, with the great Saturday vigil at St. Peter’s. It was impossible, after this exhausting night, to celebrate the solemnity of all the Saints the next morning.
The Byzantine practice was therefore abandoned, and there remained only the feast of May 13 in honor of the martyrs, instituted by Boniface IV when he consecrated the Pantheon to the Christian cult.
The thought of a collective solemnity of all the saints and not just of the martyrs remained, though.
While the Iconoclasts were destroying images and relics in the East, and in Latium, in Italy, cemeteries full of martyrs were lying abandoned because of the constant invasions of the Lombards, Gregory III erected an expiatory oratory in St. Peter’s in honor of all the Saints, Martyrs and Confessors from everywhere in the world.
A choir of monks was entrusted with the liturgical service of this sanctuary. Every day they even made a special commemoration of all the saints whose natale were celebrated by the various Catholic churches on that day.
How did Rome come to celebrate the feast of all the Saints in November? Nothing could be less clear. The change came under Gregory IV (827-844), and Louis the Pious and the Frankish bishops had something to do with it, but it is impossible to determine whether the initiative came from the pope or the emperor.
What is certain, is that it was Pope Sixtus IV (1471-1484) who later added an octave to the feast.