an abbreviation of a name by means of a character or cipher, formed by the interweaving of two or more letters with each other. They are of very ancient date, and were employed upon coins, medals, seals, &c., by not a few of the more distinguished families of Greece and Rome. They were not used by the Roman emperors till a later period. The Greek monogram for the name of Christ ΧΡ, consisting of a combination of the first two letters of Χριστός, is found on the coins of Constantine the Great; and was continued by not a few of his successors. Monograms appear frequently on coins, &c., during the middle ages, and they were frequently employed by princes (e.g., the kings of France, A.D. 751-987), and other dignitaries of that period, as a substitute for their signature. This mode of adhibiting their names to their works was frequently adopted in later times by printers, painters, and engravers; and monograms are occasionally to be met with at the present day attached to books and works of art. When all the letters which compose the word are expressed in the monogram, it is called perfect; otherwise it is said to be imperfect.

Much labour and research have been expended on the deciphering of ancient monograms, and many of them remain still unintelligible. The most valuable works on this branch of the subject are Montfaucon, Palæographia Graeca; Froelich, Annal. Reg. Syr.; Combe, Museum Hunterianum; Torremuzza, Description des Monnaies de Sicile; Pellerin, Recueil des Villes, des Peuples, et des Rois; Mionnet, Traité de la Numismatique; Le Blanc, Traité Historique des Monnaies de France. Of later monograms various treatises have taken notice; but the ablest works, since the Abbé de Marolles, in 1667, drew attention to the subject, are those of Bartsch, Peintregraveur; and especially Brulliot, Dictionnaire des Monogrammes, &c., 2 vols. 4to, Munich, 1832-34,—both works of great accuracy and research. (See Numismatics.)