A Baptism in Blood
” … Such, then, appears to have been the annual solemnisation of the death and resurrection of Attis in spring.
But besides these public rites, his worship is known to have comprised certain secret or mystic ceremonies, which probably aimed at bringing the worshipper, and especially the novice, into closer communication with his god. Our information as to the nature of these mysteries and the date of their celebration is unfortunately very scanty, but they seem to have included a sacramental meal and a baptism of blood.
In the sacrament the novice became a partaker of the mysteries by eating out of a drum and drinking out of a cymbal, two instruments of music which figured prominently in the thrilling orchestra of Attis. The fast which accompanied the mourning for the dead god may perhaps have been designed to prepare the body of the communicant for the reception of the blessed sacrament by purging it of all that could defile by contact the sacred elements.
In the baptism the devotee, crowned with gold and wreathed with fillets, descended into a pit, the mouth of which was covered with a wooden grating. A bull, adorned with garlands of flowers, its forehead glittering with gold leaf, was then driven on to the grating and there stabbed to death with a consecrated spear. Its hot reeking blood poured in torrents through the apertures, and was received with devout eagerness by the worshipper on every part of his person and garments, till he emerged from the pit, drenched, dripping, and scarlet from head to foot, to receive the homage, nay the adoration, of his fellows as one who had been born again to eternal life and had washed away his sins in the blood of the bull.
For some time afterwards the fiction of a new birth was kept up by dieting him on milk like a new-born babe. The regeneration of the worshipper took place at the same time as the regeneration of his god, namely at the vernal equinox. At Rome the new birth and the remission of sins by the shedding of bull’s blood appear to have been carried out above all at the sanctuary of the Phrygian goddess on the Vatican Hill, at or near the spot where the great basilica of St. Peter’s now stands; for many inscriptions relating to the rites were found when the church was being enlarged in 1608 or 1609.
From the Vatican as a centre this barbarous system of superstition seems to have spread to other parts of the Roman empire. Inscriptions found in Gaul and Germany prove that provincial sanctuaries modelled their ritual on that of the Vatican. From the same source we learn that the testicles as well as the blood of the bull played an important part in the ceremonies. Probably they were regarded as a powerful charm to promote fertility and hasten the new birth.”
James George Frazer, The Golden Bough: A Study in Magic and Religion (1922)
Chapter 34:: The Myth and Ritual of Attis, np.