Bookbinding and the Conservation of Books
A Dictionary of Descriptive Terminology

diptych

An ancient hinged writing tablet consisting of two tablets of wood, ivory or metal, having wax in the hollowed inner surfaces, on which writing could be done with a stylus. The hinges were generally metal rings or thongs threaded through the holes. Near the outer edge on the inside of one tablet as a small trench designed to hold the stylus, which was a small bone or metal instrument pointed at one end for writing and flat at the other end for removing writing in the wax. In the middle of each inner side a small knob protruded to keep the wax surfaces apart. Ordinary diptychs were generally made of beech, fir, or citron wood, but those made for ceremonial use, or for important recipients, were often made of ivory, sometimes beautifully carved, and fitted with gold or jewels. The most lavishly embellished specimens belong to the Byzantine period, 530 to 560. Because they were small enough to hold in one hand, in Latin they were sometimes called "pugillaria." The diptych is interesting because it is both a manuscript and a binding. (12 , 109 , 373 )