Once a Week (magazine)/Series 1/Volume 7/The monogram
The Monogram.—The monogram on the sacred standard of Constantine became for a long time conspicuous on Christian monuments in the East and West, and is now carved on most of the sepulchral tablets of modern Italy. Yet there is a mystery about what it really means, without a pretence of anything miraculous as to the way in which it came to be used. It is doubtful whether anyone besides the Emperor himself can have known whether he took its upper part to represent the Latin letter P, or the Greek one for R. The great comparative prominence of the said upper part on early monuments, joined to Constantine’s ignorance of Greek, inclines us to the former opinion, and perhaps Eusebius as an enthusiastic Oriental gave rise to the latter. There is some evidence that the Roman Emperor Probus brought the monogram, or something like it, from Egypt in the third century. His name and virtues perhaps suggested the appropriation of a sign which had long before been attached to representations of the more popular members of the Ptolemaic dynasty.