This nummus was minted in 337 CE at Constantinople, which by then had replaced Rome as the capital of the Roman empire. On the obverse it depicts the head of Constantine wearing a laurel crown, and on the reverse the labarum—a military vexillum bearing the Chi-Rho symbol, signifying the name of Christ—which we will discuss further below. In 294 CE, the emperor Diocletian introduced this large bronze denomination as part of his economic reforms. It weighed 10 grams, and was covered by a thin layer of silver, which made up just 4% of the total weight of the coin. By the time of Constantine’s death in 337 CE, the year that this coin was minted, the Diocletianic nummus had been even further debased (older scholarship referred to the Diocletianic nummus as a follis; on the Diocletianic nummus, see Constantina Katsaki, The Roman Monetary System, p. 97-98). Coinage with the mint signature CONS, as seen on the present example, had begun to be minted from 326 CE onwards, including labarum coins such as this one, displaying “the first overtly Christian reverse type” (Richard Abdy, “Tetrarchy and the House of Constantine,” p. 595). As Charles Odahl states, this coin has been regarded as perhaps the most significant of Constantine’s Christian coin types, as usually Christian imagery appears only in the form of a cross or monogram as a mark of issue or a decorative element. So, this coin must carry a particular message. Older scholars saw the speared snake as symbolising paganism more generally. However, this would not really fit with Constantine’s attitude of religious tolerance, leading Odahl to propose that the coin’s message was aimed predominantly at Constantine’s Christian subjects (Odahl, “An Eschatological Interpretation,” p. 47-48). We will discuss this possibility in the paragraphs which follow.

The inscription on the obverse of the coin refers to Constantine as Maximus, or the greatest, and Augustus, a title which served to emphasize the emperor’s sacral standing (on the meaning of this term, see the discussion of Ovid, Fasti I.587-616). The inscription on the reverse reads spes publica, which can be translated roughly as “hope of the state.” Spes, whose Greek counterpart was Elpis, was the ancient Roman goddess of hope, and a temple to Spes Vetus, possibly erected in the fifth century BCE, stood near the Praenestine Gate, one of the gates of the Servian walls. Another temple to Spes had been promised by Aulus Atilius Calatianus during the First Punic War. Spes was closely associated with other goddesses such as Concordia, the goddess of concord and harmony, and Victoria, the goddess of victory. Spes Augusta was closely associated with the emperor, and was viewed as holding the power to grant a satisfactory future to Rome. However, on the reverse of this issue, despite the inscription, we do not find a picture of the goddess (for examples of coins which picture her, see the sources linked to at the bottom of the page). Instead, this issue depicts the labarum. The labarum was a vexillum, or military standard, bearing a Christogram, the combination of the Greek letters Chi and Rho, which are the initials of the Greek word for Christ (Christos, Xριστός). According to early Christian tradition (which is not entirely consistent), this standard was adopted by Constantine on the eve of the battle of the Milvian Bridge in 312 CE, where he ultimately defeated Maxentius to become sole emperor. Lactantius, On the Deaths of the Persecutors XLIV.4-6, writes that Constantine was instructed in a dream on the eve of the battle to place the symbol of the heavenly God, i.e. the cross (caeleste signum dei) on his soldiers’ shields. The emperor did so, also marking them with the Latin letter X. The combination of these elements seems to represent a staurogram, a variant of the Chi-Rho Christogram which Eusebius describes in his Life of Constantine I.28. As Eusebius relates the story, Constantine saw a trophy (τρόπαιον, tropaion) of a cross at around noon (not in a dream as Lactantius claims) bearing the inscription “conquer/prevail (νικάω, nikaō) by this.” In the following verse, Eusebius explains that later on that evening, Constantine was told by Christ in a dream that he should use this same symbol as a safeguard in all future battles (in 350 CE, Vetranio, ruler of the Balkans during the reign of Constantius II, issued a coin commemorating this event, with the legend “HOC SIGNO VICTOR ERIS,”  “by this sign, you will be victorious”). Accordingly, shortly after, in Life of Constantine I.31, Eusebius describes the labarum as follows:

“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 center: 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” (translation by Rev. Arthur Cushman McGiffert, freely available here: https://sourcebooks.fordham.edu/basis/vita-constantine.asp).

If we follow Eusebius, then, the labarum as a personal standard of Constantine was adopted as early as 312 CE. However, this is not supported by the numismatic evidence, as the labarum appears on the reverse of coins minted by Constantine only from 319-320 CE onwards (Clive Foss, Roman Historical Coins, p. 109). Noel Lenski discusses the fact that the labarum would not necessarily have been viewed by everyone in the empire as overtly Christian, as in addition to any religious significance it was imbued with the Chi-Rho was a military symbol for Constantine, and these two elements could be separated just as much as they could be connected. For some, Lenski suggests, it would just have been another military ensign like any other. Moreover, the staurogram and even the Christogram resembled the Egyptian ankh, which was associated with the sun god Ra long before Constantine’s time, meaning that any Egyptian subjects may have seen the labarum as further connecting the emperor with the divine sun (on this theme, see the commentary on Eusebius’s In Praise of Constantine III.3-5) (Lenski, Constantine and the Cities, p. 11). Indeed, as Mark Hebblewhite states, “Under Constantine, the potency of the Labarum as a symbol of power lay in its ambiguity” (The Emperor and the Army, p. 67). While this is true, that the present coin sought to forward a message to the Christian inhabitants of the empire is something which as we shall see in the following discussion, seems clear,

In this connection, according to Patrick M. Bruun and others, the labarum was used to depict Constantine’s overthrow of Licinius, Constantine’s co-emperor and rival, whom he defeated in battle and finally executed in 324 CE, and who is presented in Constantine’s propaganda as a persecutor of Christians. In the present issue, then, Constantine’s adversary is represented as a snake, which is pierced by a spear topped with the labarum to assert Constantine’s victory over the impious tyrant (Bruun, Roman Imperial Coinage VII, Constantine, no. 19). Indeed, as Lenski points out in his discussion of the present coin, by the time Constantine defeated Licinius his victories were presented as the defeat of both Christian persecutors and also the devil himself. This metaphor was developed and allowed Constantine to connect his military campaigns with “events of theological and even cosmic significance.” Moreover, Licinius is specifically described as a “serpent” or a “snake,” both by Eusebius himself and in a letter Eusebius records from Constantine to the bishops, regarding the rebuilding of churches following his victory over Licinius the “serpent” (see Eusebius, Life of Constantine II.1; II.46; Lenski, Constantine and the Cities, p. 36-37, quotation at p. 37). Eusebius even describes a painting over the portal to Constantine’s new palace in Constantinople which depicted the emperor with his foot on a serpent pierced by the labarum (σωτήριον σημεῖον, sōtērion sēmeion, the “saving sign”). Eusebius infuses this image with biblical significance, recalling Isaiah 27:1, where the prince of darkness is described in serpentine terms (Life of Constantine III.3; see Lenski, Constantine and the Cities, p. 36; Charles Odahl, “An Eschatological Interpretation,” p. 48-49). For Eusebius at least, then, the pierced snake motif is traceable to Constantine himself. For Odahl, Eusebius’s testimony in the Life of Constantine indicates that the emperor was relatively knowledgeable of the Bible, and even drew on eschatological motifs himself. Moreover, Constantine is also recorded by Eusebius as presenting himself as God’s chosen instrument to fulfil God’s purposes on earth by defeating persecuting emperors, and leading his armies to victory under God’s “sign” (σφραγίς, sphragis)(see Life of Constantine II.24-42; II. 48-60: Odahl, “An Eschatological Interpretation,” p. 49-50). As Odahl argues, then, the pierced snake on the present coin can be understood as forwarding the message to Christian inhabitants of the empire that an era of persecution had ended and one of imperial favour had begun. Constantine was asserting that he was God’s elected leader to realise this new period of promise, which the inscription SPES PVBLICA shows (“An Eschatological Interpretation,” p. 51). We find on this coin a clear representation of Roman military power united with Christianity. The message that the coin carries is that the emperor’s armies will defeat its enemies specifically with the help of the Christian God, and in this sense it differs from the vast array of previous numismatics which portray Roman military power in connection with Roman gods.

(RIC VII, Constantine, no. 19).