p. 86 Canon XV.
The deacons ought to be seven in number, according to the canon, even if the city be great. Of this you will be persuaded from the Book of the Acts.
Ancient Epitome of Canon XV.
Seven Deacons according to the Acts of the Apostles should be appointed for each great city.
This canon was observed in Rome and it was not until the xith century that the number of the Seven Cardinal Deacons was changed to fourteen. That Gratian received it into the Decretum (Pars. I., Dist. XCIII., c. xij.) is good evidence that he considered it part of the Roman discipline. Eusebius 128 gives a letter of Pope Cornelius, written about the middle of the third century, which says that at that time there were at Rome forty-four priests, seven deacons, and seven subdeacons; and that the number of those in inferior orders was very great. Thomassinus says that, “no doubt in this the Roman Church intended to imitate the Apostles who only ordained seven deacons. But the other Churches did not keep themselves so scrupulously to that number.” 129
In the acts of the Council of Chalcedon it is noted that the Church of Edessa had fifteen priests and thirty-eight deacons. 130 And Justinian, we know, appointed one hundred deacons for the Church of Constantinople. Van Espen well points out that while this canon refers to a previous law on the subject, neither the Council itself, nor the Greek commentators Balsamon or Zonaras give the least hint as to what that Canon was.
The Fathers of Neocæsarea base their limiting of the number of deacons to seven in one city upon the authority of Holy Scripture, but the sixteenth canon of the Quinisext Council expressly says that in doing so they showed they referred to ministers of alms, not to ministers at the divine mysteries, and that St. Stephen and the rest were not deacons at all in this latter sense. The reader is referred to this canon, where to defend the practice of Constantinople the meaning of the canon we are considering is entirely misrepresented.
Eusebius, H. E., Lib. VI., cap. xliij.86:129
Thomassin, Ancienne et Nouvelle Discipline de lÉglise, Lib. II., Chap. xxix.86:130
Acta Conc. Chal., Actio x.