Diptych

(Or diptychon, Greek diptychon from dis, twice and ptyssein, to 
fold). 

A diptych is a sort of notebook, formed by the union of two 
tablets, placed one upon the other and united by rings or by a 
hinge. These tablets were made of wood, ivory, bone. or metal. 
Their inner surfaces had ordinarily a raised frame and were 
covered with wax, upon which characters were scratched by means of 
a stylus. Diptychs were known among the Greeks from the sixth 
century before Christ. They served as copy-books for the exercise 
of penmanship, for correspondence, and various other uses. The 
Roman military certificates, privilegia militum, were a kind of 
diptych. Between the two tablets others were sometimes inserted 
and the diptych would then be called a triptych, polyptych, etc. 
The term diptych is often restricted to a highly ornamented type 
of notebooks. They were generally made out of ivory with carved 
work, and were sometimes from twelve to sixteen inches in height. 
In the fourth and fifth centuries a distinction arose between 
profane and ecclesiastical (liturgical) diptychs, the former being 
frequently given as presents by high-placed persons. It was 
customary to commemorate in this way one's elevation to a public 
office, or any event of personal importance, e.g. a marriage. The 
consuls, on the day of the installation, were wont to offer 
diptychs to their friends and even to the emperor. Those presented 
to the latter often had a border of gold and were quite large. 
Their tablets often exhibited on a central plate the portrait of 
the sovereign, surrounded by four other plates. The (undated) 
Barberini ivory at the Louvre is thus constructed and once served 
as an ecclesiastical diptych (see below). Some believe it to be 
the binding of a books offered to the emperor. Strzygowski holds 
it to be of Egyptian origin and thinks that the portrait is that 
of Constantine the Great, defender of the Faith. The oldest dated 
consular diptych is that of Probus (406); it is kept in the 
treasury of the cathedral of Aosta, Piedmont. The latest is that 
of the Eastern consul, Basilius (541), one tablet of which is at 
the Uffizi Museum in Florence and the other at the Brera in Milan. 
The Theodosian Code (384) forbade the offering of ivory diptychs 
to any but the regular (i.e. not honorary) consuls. The tablet at 
the Mayer Museum in Liverpool, bearing the image of Marcus 
Aurelius (d. l80), is prior to this enactment. The consular 
diptychs are recognizable by their inscriptions or by the figure 
of the consul which they bear. On the diptych of Boetius at 
Brescia (487) and several others of the same type the consul is 
clad in a trabea (a kind of toga); he holds in his left hand the 
scipio (consular sceptre) and in his right the mappa circensis, or 
white cloth which he used to wave as the signal for the games in 
the circus. These games (ludi) or other liberalities offered to 
the people by the consul were frequently represented on the 
tablets of the diptychs. 

There is less certainty concerning the diptychs of officials other 
than consuls, e.g. praetors, quaestors, etc. The diptych of Rufius 
Probianus V. C. (i.e. vir clarissimus) vicarius urbis Romae, in 
the Berlin Museum, is the most precious relic of this class, and 
probably dates from the end of the fourth century. Among the 
diptychs of private individuals that of Gallienus Concessus, 
discovered at Rome on the Esquiline, exhibits only the name of its 
owner. Others were richly ornamented and reproduced often some of 
the masterpieces of ancient art. Thus on a diptych in the Mayer 
Museum, Liverpool, are seen Aesculapius and Telesphorus Hygieia, 
and Amor. The most beautiful of the profane diptychs was carved at 
the time of a marriage between the Symmachi and the Nicomachi (392 
to 394, or 401). It represents on each leaf (one of which is at 
the South Kensington Museum and the other, in a very damaged 
condition, at Cluny) a woman performing a sacrifice. Many of the 
profane diptychs were preserved in the treasuries of the churches, 
where they were eventually used for liturgical purposes or 
enshrined in bookbindings or in goldsmith work. The diptych of 
Boetius, among others bears on the interior, some liturgical texts 
and religious paintings, attributed to the seventh century. The 
Liege diptych of the consul Anastasius (517), one leaf of which is 
at Berlin and the other at South Kensington, bears an inscription 
of forty-two lines and the prayer Communicantes from the Canon of 
the Mass. Another of the same consul (in the