TAVOLETTE CERATE. - Writing material of common use adopted extensively by the ancients and sporadically almost down to our own day: they were used above all for accounts, letters, notes, school exercises, and also for contracts and testaments. They consisted of small rectangular boards of wood or ivory, with raised rims around the edges, into the hollow of which was poured molten wax mixed with pitch; once cooled, one wrote upon it by incising it with a stylus. Waxed on one or both sides, they could be single or joined together (by means of binding or metal rings), in twos, threes, fours, and more (diptycha, triptycha, polyptycha).
Among the wooden t. c. preserved to us from antiquity, the two most conspicuous groups are represented by the Dacian tablets (found in Transylvania, in the mines of Verespatak, between 1788 and 1855) and the Pompeian ones (discovered in 1875 in the excavation of the house of the banker L. Caecilius Jucundus): but those from Herculaneum, Egypt (among these one, now in Geneva, containing the text of Ps. 91: cf. J. Nicole, Textes grecs inédits de la collection papyrologique de Genève, Geneva 1909, no. 6), and Tunisia are also very important, both from a palaeographical and from a legal point of view. Among the ivory tablets, particular prominence is deserved by the consular diptychs, richly carved on their outer faces, which consuls and magistrates gave to their friends when entering office; repurposed for liturgical uses, above all as covers for sacred books in the Middle Ages and at the beginning of the modern era, they have come down to us in a considerable number.