This feast was originally kept in the springtime in the Eastern Church, and dedicated to ‘the martyrs of the whole world’ as witness by John Chrysostom and Ephrem of Syria. In the West, Maximus of Turin preached on the same feast on the same day, the first day of Pentecost.
On 13 May 610, Pope Boniface IV gathered up around 28 wagonloads of bones of martyrs that had been plundered from the catacombs by invaders, and reinterred them beneath the Pantheon in Rome, a pagan temple built by the Emperor Hadrian, which had been dedicated to all the gods. Pope Boniface rededicated this shrine to St Mary and the Martyrs. Many historians see this as the origin of All Saints Day.