by pagan Greek scribes to mark, in the margin, a particularly valuable or relevant passage: the com-
bined letters
chi
and
rho
stand for χρηστ ν [chr¯eston], meaning “good”) with the phrase “ Εν το τω
ν κα” (“Conquer by this”) spelled out in the sky. Eusebius relates that Constantine told him this story
long after the event is said to have occurred, and given the surprise that Eusebius expresses at having
been told this story by Constantine, it’s clear that the claimed event was commonly unknown. However,
Eusebius also conveys that Constantine’s whole army saw the miracle in the sky, and had that been the
case it would have been widely known. Eusebius implies that this vision took place before Constan-
tine’s campaign against Maxentius began (ibid., Ch. 37, p. 492), and therefore well-before the Battle
of the Milvian Bridge, which took place on October 28, 312 between the Roman Emperors Constantine
and Maxentius at which Maxentius was defeated and killed. The Arch of Constantine, the triumphal
arch that Constantine had built to commemorate his victory in the Battle of the Milvian Bridge, which
Constantine dedicated in summer 315, features a stone panel engraved with the depiction of a Roman
emperor sacrificing a hog (sus), a ram (ovis), and a bull (taurus) to the Roman god of war, Mars (a
ritual known as
suovetaurilia, combining the three species’ names into one word); and statuettes of Sol
Invictus carried by standard-bearers appear in three places in reliefs on the arch. Yet there is no Chris-
tian symbolism on the arch (not even the Chi Rho, which at any rate had no connection to Christianity
in the popular mind or among common Christians at that time, as it only later came to be commonly
understood as a monogram for Χριστ σ [Christos], meaning “Christ”).
Eusebius in his earlier work
Church History
[128,
Book 9, Ch. 9, pp. 363–364] promotes the idea
that God helped Constantine win the Battle of the Milvian Bridge, but does not mention any vision.
This implies that Eusebius at this time didn’t know of any such vision by Constantine (and hence that it
was commonly unknown), as given the profuse laudation that Eusebius heaps upon Constantine in this
passage, Eusebius surely would have mentioned the vision as demonstration of Constantine’s favor with
God, unless Eusebius himself found the story to be so dubious that he didn’t want to taint his
Church
History
with it (which, if so, itself implies that the purported event was popularly unknown).
Lactantius, a rhetorician who was an advisor to Constantine I, tells a different story from Eusebius’s
account of Constantine’s vision (which Eusebius is careful to emphasize was told to him directly by
Constantine). Lactantius wrote that in the night before the Battle of the Milvian Bridge, Constantine was
commanded in a dream by an unspecified source to put a divine heavenly sign (described by Lactantius
as the Chi Rho symbol) on the shields of his soldiers, and that Constantine followed the command of his
dream and marked the shields with this sign (Ref.
358,
Of the Manner in Which the Persecutors Died, Ch.
44, p. 318). Lactantius died ca. 320, whereas Eusebius wrote his
Life of Constantine
after Constantine
died in 337. Thus, at best it appears that Constantine had a dream containing no specific Christian
content that he later conflated to something more.
Constantine’s official coinage continued to bear images of Sol Invictus, the official Sun god of the later
Roman Empire, until 325/326. Constantine retained until his death the office of Pontifex Maximus,
the high priest and head of the pagan state religion of Rome, as would his successors, with Gratian
(Emperor of Rome from 375–383) finally renouncing the title. Constantine was baptized as a Christian
on his deathbed.