DIPTYCHA, in Antiquity, a public register, wherein were written the names of the consuls and other magistrates, among the heathens; and of bishops, and defunct as well as surviving brethren, among the Christians.

The word is formed from the Greek o∕σrυ^ωt∣, or bιπ- l rυχμ, and that from ⅛m∣ξ, a masculine noun derived from •πτνΰΰω, I fold or plait. From its future πruξω is formed <rτuξ, a fold or plait, to which adding i>ις, twice, we have δ∕5Γτυξ, in the genitive bιπτυγj>ς, whence comes the nominative neuter 0ικτυ∙χρν, a booh folded in two leaves ; though there were some in three, and others in four or five leaves. An ingenious author imagines this name to have been first given them in order to distinguish these leaves from the books which were rolled, and hence called volumina.

It is certain there were profane diptycha in the Greek empire, as well as sacred ones in the Greek church. The former were the matricula or registers, wherein the names of the magistrates were entered; in which sense diptycha is a term in the Greek chancery.

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 [7:8:39] 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 Athenaeus (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 Mamercus 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. cxvi. 15). Rosweydadds Ecclesiasticus (xliv. 1), and takes these to have been the passages the ancient church had a view to, rather than the Sal inn 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. Ludor, in C. Theod. forbids all magistrates below the rank of consuls to make presents of diptycha of ivory in the public ceremonies.