"At a solemn mass the oblation was hallowed by the united prayers of the whole college of presbyters, voiced by their head, the bishop. The presbyters stand around their bishop, and, as a ninth century Gallican writer [‘Presbyteri e regione dextra laevaque… consensum eius praebeant sacrificio (Gratiani Decreti pars iii, De consecr.: dist. I: cap. Lix, Episcopus Deo)] express it, ‘give consent to his sacrifice.’ But the Roman Church at an early period adopted another method. In the Life of Zephyrinus we are told that he established the custom og holding glass patens before the presbyters, and for deacons to hold them whilst the bishop celebrated mass, standing upright by him. We can gather from this that the earlier practice, by which the bishop consecrated the oblation with the assent of his presbyters, was at some time (which may or may not have been during the pontificate of Zephyrinus, 200-218) changed to another, whereby each presbyter consecrated a portion of the oblation, held before him by one of the deacons on a glass paten, simultaneously with the pope. This rite persisted in the eighth and ninth centuries, but only on certain high festivals. The St. Amand Ordo gives these as Christmas, Epiphany, Easter day (both at the midnight mass and that on the day itself), Ascension day, Whitsunday, and SS. Peter and Paul. At ordinations and consecrations of churches it obtained for a much longer period. In the ninth century the patens of glass had been replaced by corporasses, and each presbyter hallowed two or three loaves" - E. G. Cuthbert, F. Atchley, L.R.C.P., M.R.C.S, Ordo Romanus primus, London 1905, pp. 113-114.
From Ordo Romanus primus (F. Atchley, Ordo Romanus primus, p. 148):
48. In diebus festis, id est, Paschae, Pentecostes, sancti Petri, Nativitatis Domini, per has quattuor sollemnitates habent colligendos presbyteri cardinales, unusquisque tenens corporalem in manu sua: et venit archidiaconus et porrigit unicuique eorum oblatas tres. Et accedente pontifice ad altare, dextra laevaque circumdant altare, et simul cum illo canonem dicunt, tenentes oblatas in manibus, non super altare, ut vox pontificis valentius audiatur; et simul consecrant corpus et sanguinem Domini: sed tantum pontifex facit super altare crucem dextra laevaque.English translation (F. Atchley, Ordo Romanus primus, p. 149):
48. On festivals, that is to say on Easter day, Pentecost, St. Peter’s day, and Christmas day, the cardinal presbyters assemble, each one holding a corporas in his hand, and the archdeacon comes and offers each one of them three loaves. And when the pontiff approaches the altar, they surround it on the right and the left, and say the canon simultaneously with him, holding their loaves in their hands, and not placing them on the altar, so that the pontiff’s voice may be heard the more strongly, and they simultaneously consecrate the body and blood of the Lord, but the pontiff alone makes a cross over the altar.