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

The word is formed from the Greek διπτυχων, or διπτυχια, and that from διπτυχι, a masculine noun derived from διπτυχι, I fold or plait. From its future πτερον is formed πτερος, a fold or plait, to which adding δις, twice, we have διπτυχι, in the genitive διπτυχιους, whence the nominative neuter διπτυχιον, q. d. a book 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, to distinguish them from the books that were rolled, 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 whereof 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; several saints are invoked in different times, &c. In these diptycha were entered the names of bishops, who had governed their flock aright; and these were never expunged out of the same, 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 they would do any signal honour to, in the verses of the Salii; as was done to Germanicus and Verus, sons of the emperor Marcus Aurelius, and a long time before, during the age of the republic, to Mamercus Veturius, and Lucia Volumnia, as we are told by Tacitus, lib. ii. Spartan, Ovid, Festus, Plutarch, &c. But Fa. Rofweyd does not approve this notion of Casaubon. The pretended St Dionysius, a very ancient author, lays the contrary, and affirms the first establishment of this usage to have been founded on Scripture, 2 Tim. ii. 19. Pfal. cxvi. 15. Rofweyd adds Ecclesiastic. xiv. 1. and takes these to have been the passages the ancient church had a view to, rather than the Sallian verses.

The profane diptycha were frequently sent as presents to princes, &c. on which occasions they were finely gilt, and embellished; as appears from Symmachus, lib. ii. ep. 81. Those presented were usually of ivory. The first law, De Expenf. Ludor. C. Theod. forbids all magistrates below consuls to make presents of diptycha of ivory in the public ceremonies.