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Early Christian Types
The first type to refer to Christianity was struck in 327-328 under Constantine (307-337), but its reference to Christianity, while evident, is obscure. It has provoked many scholarly articles.
This coin: 18 mm. 2.99 grams.
Head of Constantine right, laureate.
CONSTANTI-NVS MAX AVG
Reverse: SPES PVBLIC across the field with A in the lower left field,
a chi-rho topping a standard
with three dots on the vexillum (flag-like object), planted in a serpent with head downward.
CONS (indicating the mint of Constantinople) in exergue.
RIC Constantinople 19
This type was issued only in the first issue of the new mint at the newly founded capitol city of Constantine, Constantinopolis (now Istanbul in Turkey, which was founded on the site of a smaller Greek city named Byzantium, for which the Byzantine empire is named). It must have been unpopular when it was issued in 326 because it was almost immediately discontinued; the other coin types of the same issue are far more common. No other ancient coin type is similar enough to help us interpret this type, and each proposed interpretation has been disputed by some other author with a different interpretation.
"SPES" means "hope" and had appeared on coins many times. A personification of Spes is a common type for the emperor's son and heir apparent. But there never had been anything like a standard planted in a snake. The snake has been interpreted as a symbol of evil in general or, alternatively, as a symbol for Licinius, the defeated rival emperor of the eastern part of the empire. In any case, the interpretation goes, the standard of Christianity defeated them, causing the head of the snake to droop as if in death. The three dots on the standard might, or might not, show medallions portraying Constantine's three sons.
There are many off-site discussions of this type. One is here (a very old Numismatic Chronicle issue on googlebooks). Victor Clark, at http://www.constantinethegreatcoins.com/symbols/ says
"Constantine, and Eusebius, compared serpents/dragons to evil on many occasions. In one instance, when he referred to Arius, Constantine talked about the serpent and the Devil as if they were one. Constantine also used the dragon/serpent symbolism to specifically describe Licinius. "Like some, or a twisting snake coiling up on itself." "But now, with liberty restored and that dragon driven out of the public administration through the providence of the supreme God and by our service."
In a CoinTalk post ( https://www.cointalk.com/threads/constantine-i-spes-pvblic-from-constantinople.384563/#post-7811241 )
Victor Clark, an expert on Constantine, wrote:
Constantine used the dragon/serpent symbolism to specifically describe Licinius.
"But now, with liberty restored and that dragon driven out of the public administration through the providence of the supreme God and by our service." (Eusebius Vita Constantini Book 2, Chapter 46.2).
"Like some wild beast, or a twisting snake coiling up on itself. (Eusebius Vita Constantini Book 2, Chapter 1.2).
"The references to "liberty...restored" and the perishing dragon-serpents in the palace sermon and the episcopal letter must be the literary twins of the LIBERTAS PVBLICA and the pierced dragon coins issued about the same time." (Charles Odahl. “The Use of Apocalyptic Imagery in Constantine's Christian Propaganda.” Centerpoint 4, no. 3 (1981) : 17.).
Eusebius also described a painting that Constantine placed above the door to his palace.
“This he displayed on a very high panel set before the entrance to the palace for the eyes of all to see, showing in the picture the Saviour's sign placed above his own head, and the hostile and inimical beast, which had laid siege to the Church of God through the tyranny of the godless, he made in the form of a dragon borne down to the deep. For the oracles proclaimed him a 'dragon' and a 'crooked serpent' in the books of the prophets of God (Isaiah 27:1); therefore the emperor also showed to all, through the medium of the encaustic painting, the dragon under his own feet and those of his sons, pierced through the body with a javelin, and thrust down into the depths of the sea.” (Eusebius Vita Constantini Book 3, Chapter 3).
The coin shows three medallions on the standard. The medallions were portraits of Constantine I and two of his sons. The sons were probably Constantine II and Constantius II, as Eusebius said that Constantine personally showed him the standard. Eusebius did not meet Constantine until 325, and Crispus was dead by 326, so the other two sons are the most likely candidates to have been represented on the standard; otherwise the story might have been a little awkward.
Note for collectors: This type is very rare and in great demand. A nice example will cost more than two thousand dollars. At most times there will be none on the market and when the next one appears, which might be year or more off, it is likely to appear in a major auction. The type has been the subject of modern counterfeiting, as described here.
In AD 350 the first type with an overtly Christian legend occurs. Vetranio, ruler in the Balkans during the reign of Constantius II, issued this historically important first type with the legend "HOC SIGNO VICTOR ERIS" ("In this sign, you will be victorious") referring to the famous vision of Constantine prior to the battle of the Milvian bridge on October 28, 312.
This coin: Obverse portrait of Vetranio, who ruled in the Balkans March 15 - Dec. 25, 350.
21 mm diameter. 5.06 grams.
Bust of Vetranio right, laureate, draped, and cuirassed
Legend: DN VETRA-NIO PF AVG, A in field left, star in field right
Reverse: HOC SIG-NO VICTOR ERIS
Victory crowning emperor holding standard with chi-rho, A in field left.
• ASIS • mintmark in exergue, for the Siscia mint (now Sisak in modern Croatia).
RIC Siscia 287
The chi-rho, 
, (also called a christogram, or, rarely in numismatics, a chrismon) is formed from the first two letters of "Christ" in Greek (chi = X and rho = P).
This is a reference to the famous vision of Constantine before the momentous Battle of the Milvian Bridge against Maxentius just outside Rome on October 28, 312. The ancient author Lactantius who was tutor to Crispus (appointed either 311 or 313) wrote in "On the Deaths of the Persecutors" (c.318-321, Chapter 44, a.k.a. "On the Manner in which the Persecutors died"):
"Constantine was directed in a dream to cause the heavenly sign to be delineated on the shields of his soldiers, and so to proceed to battle. He did as he had been commanded, and he marked on their shields the letter X, with a perpendicular line drawn through it and turned round thus at the top (P), being the cipher of CHRISTOS. Having this sign, his troops stood to arms.
This testimony is reliable (as the next coin supports) and differs from the report written twenty-five years after the event by Eusebius who wrote in "The Life of Constantine":
"He said that about noon, when the day was already beginning to decline, he saw with his own eyes the trophy of a cross of light in the heavens, above the sun, and bearing the inscription, CONQUER BY THIS. At this sight he himself was struck with amazement, and his whole army also, which followed him on this expedition, and witnessed the miracle.
"He said, moreover, that he doubted within himself what the import of this apparition could be. And while he continued to ponder and reason on its meaning, night suddenly came on; then in his sleep the Christ of God appeared to him with the same sign which he had seen in the heavens, and commanded him to make a likeness of that sign which he had seen in the heavens, and to use it as a safeguard in all engagements with his enemies.
"At dawn of day he arose, and communicated the marvel to his friends: and then, calling together the workers in gold and precious stones, he sat in the midst of them, and described to them the figure of the sign he had seen, bidding them represent it in gold and precious stones. And this representation I myself have had an opportunity of seeing.
"Now it was made in the following manner. A long spear, overlaid with gold, formed the figure of the cross by means of a transverse bar laid over it. On the top of the whole was fixed a wreath of gold and precious stones; and within this, the symbol of the Saviour’s name, two letters indicating the name of Christ by means of its initial characters, the letter P being intersected by X in its centre: and these letters the emperor was in the habit of wearing on his helmet at a later period. From the cross-bar of the spear was suspended a cloth, a royal piece, covered with a profuse embroidery of most brilliant precious stones; and which, being also richly interlaced with gold, presented an indescribable degree of beauty to the beholder. This banner was of a square form, and the upright staff, whose lower section was of great length, bore a golden half-length portrait of the pious emperor and his children on its upper part, beneath the trophy of the cross, and immediately above the embroidered banner. The emperor constantly made use of this sign of salvation as a safeguard against every adverse and hostile power, and commanded that others similar to it should be carried at the head of all his armies."
The standard with a chi-rho is called a "labarum." The coin above has a clear example. Far more Roman coins with early Christian symbols have a labarum with a chi-rho than have a cross.
Note for collectors: Vetranio's coins are scarce so any Vetranio coin is in demand as a portrait piece. This type is also important as an early Christian reference. These two features combine to make the type far more expensive than most fourth-century copper coins. Nevertheless, it is readily available on the market. It is usually fairly well-struck. The chi-rho is small and is sometimes not clear, in which case the historical interest is not illustrated and the coin is less desirable.
The first fully Christian design
Not long after the Vetranio type, the Gallic usurper Magnentius (AD 350-353) issued a large coin in which a chi-rho is the type.
This coin: 27 mm. 8.84 grams.
Struck 352
Bust of Magnentius right, head bare
Legend: DN MAGNEN-TIVS PF AVG
Reverse: SALVS DD NN AVG ET CAES
large chi-rho with alpha and omega on either side.
TRS in exergue (a mint mark for Trier = Treves = Treveri,
in modern Germany, near its border with Luxembourg)
The "S" denotes a product of the mint's second officina [workshop]
RIC Trier 318
The "AVG ET CAES" refers to Magnentius, the AVGustus, and his brother, Decentius, whom he had elevated to the rank of CAESar. The type is also issued for Decentius.
Not only is the chi-rho a Christian reference, but so is the alpha (A) and omega (ω) pair. Alpha is the first letter in the Greek alphabet and omega the last. In the book of Revelations (1:8) it says "I am the alpha and the omega, the first and the last." This may refer to God or to Jesus (It is a matter of scholarly dispute which. See Wikipedia for more on that distinction)
Note for collectors: Coins of Magnentius are readily available and this large type is not rare, but because of its manifest Christian connection it is several times as expensive as many other late Roman coin types. It is issued at several mints and also issued for Decentius. The denomination is called a "double maiorina" (or by size, an "AE1") and there is a very similar, but smaller and much less common, (single) maiorina of the same design. Often this type are crowded, with the flans somewhat too small for the dies. Also, this type was widely copied unofficially and imitations are found with workmanship of varying quality, from nearly as good as official mint products to quite crude.
Return to the main page for the first Christian references on Roman coins, which were only small Christian symbols, either a chi-rho ( ) or a cross somewhere in the design (c. AD 315-326, Table 1 lists the earliest ones).