(τὰ δίπτυχα) contained especially the pames of bishops, whether living or dead. The primary custom would seem to be, that they were read after the oblation of the bread and wine, and before the consecration.
(1) Sometimes they were read by the deacon.
(2) In some churches it would appear that the subdeacon recited the names on the diptychs behind the altar.
(3) Frequently the priest himself repeated the names.
(4) A curious plan is that mentioned by Fulcuin, where the subdeacon whispered the names to the priest.
(5) We find even that in some cases the tablets were merely laid upon the altar, with the names of the offerers and benefactors, of whom the priest made general mention. In the church of Ravenna, a chasuble was made to serve the purpose of a diptych.
The name of diptych was also given to registers in which were entered, as occasion required, the names of newly baptized persons, as then first becoming members of the Christian family.
Of all extant specimens, the one which is usually called the "Diptych of Rambona, in Picenum," is the most ancient and extraordinary. It contains a medallion of the First Person of the Trinity above, with the sun and moon below on the right and left of the cross, personified as figures bearing torches. There are two titles, EGO SUM IHS NAZARENUS, in rude Roman letters, with a smaller label, REX JUDEORUM, over the cross. The nimbus is cruciform, the waistcloth reaches almost to the knees, the navel is strangely formed into an eve. The Virgin and St. John stand under the arms of the cross. But the distinguishing detail is the addition of the Roman wolf and twins below the cross, with the words ROMULUS ET REMULUS A LUPA NUTRITI. This wonderful ivory is now in the Vatican Museum (see Murray's Hand-book), and is in the most ancient style of what may be called dark-age Byzantine art, when all instruction and perception of beauty are departed, but so vigorous a sense of the reality of the fact remains as to render the work highly impressive.