Nicene and Post-Nicene Fathers, Ser. II, Vol I:
The Life of Constantine with Orations of Constantine and Eusebius.: Chapter XXXVII

Chapter XXXVII.—How the Copies were provided.

Such were the emperor’s commands, which were followed by the immediate execution of the work itself, which we sent him in magnificent and elaborately bound volumes of a threefold and fourfold form. 3336 This fact is attested by another letter, which the emperor wrote in acknowledgment, in which, having heard that the city Constantia in our country, the inhabitants of which had been more than commonly devoted to superstition, had been impelled by a sense of religion to abandon their past idolatry, he testified his joy, and approval of their conduct.

Footnotes

[The parchment copies were usually arranged in quaternions, i.e. four leaves made up together, as the ternions consisted of three leaves. The quaternions each contained sixteen pages, the ternions twelve (Valesius in loc.).—Bag.] So probably, although the three-columned form of the Sinaiticus and the four of the Vaticanus suggest a possible other meaning.