SACRED DIPTYCHA. The word is plural; diptycha being a double catalogue, in one part of which were written the names of the living, and in the other those of the dead, which were to be rehearsed during the office. We meet
with something not unlike the sacred diptycha of the Greeks in the canon of the mass according to the Latin usage, where the people are enjoined to pray once for the living and once for the dead, and where several saints are invoked in different times. In such diptycha were entered the names of bishops, who had governed their flock aright; and these were never expunged, unless they were convicted of heresy or some other gross crime. In the diptycha were likewise entered the names of such as had done any signal service to the church, whether they were living or dead; and mention was made of them in the celebration of the liturgy.
Casaubon, in his observations on Athenæus (lib. vi. cap. 14), supposes the Christians to have borrowed the custom of writing names in a book, and rehearsing them at mass, from the heathens, who entered the names of persons to whom they wished to do any signal honour, in the verses of the Salii, as was done in the case of Germanicus and Verus, sons of the emperor Marcus Aurelius, and a long time before, during the age of the republic; in that of Mamerus Veturius and Lucia Volumnia, as we are told by Tacitus, Spartian, Ovid, Festus, Plutarch, and others. But Rosweyd does not approve of this notion of Casaubon; and the pretended St Dionysius, a very ancient author, asserts that this usage was originally founded on Scripture (2 Tim. ii. 19; Psal. exvi. 15). Rosweyd adds Ecclesiasticus (xlv. 1), and takes these to have been the passages the ancient church had a view to, rather than the Salian verses.
The profane diptycha were frequently sent as presents to princes and others, on which occasions they were finely gilded and embellished; as appears from Symmachus (lib. ii. ep. 81). Those presented were usually of ivory. The first law, De Expens. Lidor. in C. Theod. forbids all magistrates below the rank of consuls to make presents of diptycha of ivory in the public ceremonies.