“ 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. ”