MONOGRAM (from Late Lat. monogramma, in Late Gr. HovcypaiJ.iJ.ov, from fj.6vos, single, 7p<zju/ia, letter), originally a cipher consisting of a single letter, now a design or mark consisting of two or more letters intertwined together. The letters thus interlaced may be either all the letters cf a name, or the initial letters of the Christian and surnames of a person for use upon note-paper, seals, etc. Many of the early Greek and Roman coins bear the monograms of rulers for whom or the towns in which they were struck. The Late Latin and Greek words were first applied to the signatures, which took this form, of the emperors of the Eastern Empire. The signatures of the Prankish kings also took the form of a monogram. The accompanying monogram, from a coin of Charles the Bald, is a good example i of a " perfect " monogram, in which all the letters of the name Karolus can be traced (see DIPLOMATIC and AUTOGRAPH). The most famous of monograms is that known as the " Sacred Monogram," formed by the conjunction of the two initial letters of Xpjoros, Christ. The most usual form of this is the symbol ^, and sometimes the o (alpha) and u> (omega) of the Apocalypse were placed on either side of 'it. The symbol was incorporated in the Labarum (q.v.) when the imperial standard was Christianized. The interlaced I.H.S. (also called " The Sacred Monogram ") apparently possesses no great antiquity; it is said to have been the creation of St Bernard of Siena in the middle of the century. Monograms or ciphers were often used by the early printers as devices, and are of importance in fixing the identity of early printed books. Similar devices have been used by painters and engravers. The middle ages were, indeed, extremely prolific in the invention of ciphers alike for ecclesiastical, artistic and commercial use. Every great personage, every possessor of fine taste, every artist, had his monogram. The mason's mark also was, in effect, a cipher. As the merchant had as a rule neither right nor authority to employ heraldic emblems, he therefore fell back upon plain simple letters arranged very much in monogram form. These " merchants' marks " generally took the form of a. monogram of the owner's initials together with a private device. They nearly always contain a cross, either as a protection against storms or other catastrophes, or as a Christian mark to distinguish their goods from Mahommedan traders in the East. There is a fine example of a 16th century gold ring with a merchant's mark in the British Museum. One of the most famous of secular monograms is the interlaced " H.D." of Henri II. and Diane de Poitiers. Upon every building which that king erected it was sown profusely; it was stamped upon the buildings in the royal library, together with the bow, the quiver and the interlocked crescents of Diana. It has been argued that " H.D." is a misreading of " H.C.," which would naturally point to husband and wife; but the question is set at rest by the fact that Henri II. sometimes signed his letters to Diane with this very monogram. Henri IV. invented a punning cipher for his mistress Gabrielle d'Estrees, the surname being represented by a capital S. with a trait, or stroke through it.
See F. Builliot, Dictionnaire dzs monogrammes (1832-1834, 3 parts) ; G. K. Nagler, Die Monogrammisten (1857-1876, 5 parts); Ris-Paquot, Dictionnaire encyclopedique des marques et monogrammes, chiffres, etc. (}8<J3); also Du Cange, Clossarium (s.v. Monogramma), with plates giving examples of the monograms of early popes, the emperors of the Western Empire, and of other kings.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)