For a general introduction to the Life of Constantine, please see the commentary on I.8.

The above extracts include what is probably the most famous passage in the Life of Constantine, on which many have based the assumption that Constantine’s conversion to Christianity occurred just prior to his battle against Maxentius at the Milvian Bridge, just outside Rome, on the 28^th of October 312 CE (for a succinct account of the battle and the events preceding it, see David Potter, Constantine the Emperor, p. 137-144). The famous vision of Constantine, in which Christ’s cross is seen accompanied by the message “conquer/prevail (νικάω, nikao) by this” has received much attention over the years. However, as we shall see, it is difficult to attribute much historicity to the events precisely as Eusebius describes them. The narrative above forms part of Eusebius’s cleverly crafted portrayal of Constantine as the pious, divinely chosen sole ruler of a re-united Roman Empire. The account of Constantine’s vision and dream draw on established tropes within imperial panegyric and traditions surrounding the Roman emperors, and therefore must be understood within these wider contexts, and not taken at face value. Indeed, scholarly opinion regarding the events has varied. Some argue that the vision was not particularly significant, as Constantine had already converted to Christianity, others claim that the dwindling popularity of pagan cults meant Christianity’s eventual success did not require imperial patronage, and others still suggesting that it was simply political cunning, as Constantine continued to support pagan gods all the same (see Raymond Van Dam, Remembering Constantine, p. 4; Paul Stephenson argues that Eusebius’s narrative squashes around a decade of events into one episode, and that by the time Constantine met Eusebius in 325, the emperor “saw his conversion not as a process over a decade, but rather as a moment of revelation on which he acted decisively”: see Roman Emperor, Christian Victor, p. 184).

Eusebius’s description of the battle is based on his account in the Ecclesiastical History IX.9.2-8, except in this previous version, no vision is mentioned. In the Life of Constantine, written around twenty-five years or so later, Eusebius elaborates his account, claiming to have heard it from the mouth of the emperor himself. It is possible that he heard Constantine talking about his conversion when the two met at the Council of Nicaea in 325 CE, or perhaps on another occasion some time later. Certainly, it is important for Eusebius to assert that he had heard about the events directly from the emperor’s mouth, and that he had assured their truth by swearing an oath. Moreover, Eusebius makes sure that the entire army also witness the miracle, in order to establish further credibility. When writing the Life of Constantine, in order to ensure the emperor was portrayed in the manner that Eusebius wished, he needed a miracle, and one which he could list as corroborated. The vision of Christ, which I.28 claims was also witnessed by the emperor’s entire army, and the truth of which was sworn in an oath by Constantine, fulfilled this requirement nicely (see Averil Cameron and Stuart Hall, Life of Constantine, p. 204). Eusebius’s account differs from that of Lactantius in his On the Deaths of the Persecutors XLIV, which was written much closer to the time of the battle itself, before 315 CE. Another Christian author, Lactantius, writes that Constantine was instructed in a dream on the eve of the battle to place the symbol of the heavenly God (caeleste signum dei) on his soldiers’ shield. The emperor did so, also marking them with the Latin letter X, which seems to represent a staurogram, a variant of the Chi-Rho Christogram which Eusebius describes. In Eusebius’s account, the vision and dream occur during a previous campaign (Constantine had previously been in Britain and Gaul), while the emperor was praying, asking for the deity that was currently aiding his success to identify himself (I.28). The vision and dream that Eusebius describes are therefore somewhat separated from the battle at the Milvian Bridge. For Cameron and Hall, historians have created problems by attempting to assimilate the events described by Eusebius with Lactantius’s account of Constantine’s dream on the eve of the battle against Maxentius; rather, they suggest these two accounts ought not to be equated (Life of Constantine, p. 207).

It should be recalled that dreams and visions, especially at poignant moments in battle, had an established history among Roman leaders, with emperors such as Scipio Africanus, Sulla, Julius Caesar, and Aurelian also reported as having them. In addition, Lactantius’s account ought also to be understood in light of Judas Maccabeus’s dream in 2 Maccabees 15:11-16, which he tells to inspire his troops. Moreover, important for the consideration of Constantine’s vision/s, is another vision described in an anonymous panegyric delivered in 310 CE. Here, the emperor is described as having a vision of Apollo, accompanied by the goddess of victory, Victoria, offering Constantine laurel crowns marked with XXX, symbolising that he would reign for thirty years (Panegyrici Latini VI.21.3-4; see C. E. V. Nixon and Barbara Rodgers, In Praise of Later Roman Emperors, p. 248-251, for the text and notes). The image of numerals within a wreath featured on vota coins, distributed to the army as donatives in exchange for prayers. In the fourth century, these prayers were specifically for the virtus Augusti, the emperor’s courage to rule with divine favour. They were offered at the start and end of the anniversary year, on the date of the emperor’s accession (see Paul Stephenson, Roman Emperor, Christian Victor, p.). Constantine had taken Apollo as his patron god, and had attributed his defeat of Maximian to him. This was significant because it meant that Constantine was no longer tied to the gods assigned to him by his father and Maximian. As Stephenson has identified, this is made clear on coins and monuments (earlier coins show the emperor with Mars; interestingly, this relationship is still shown on coins minted after 312 CE, which suggests that older links were still maintained; see Follis depicting the head of Constantine and Mars, the god of war).

In 310 CE, Constantine claimed that he and his father descended from the emperor Claudius II Gothicus, whose patron god was Sol Invictus. Sol was an eastern version of Apollo, and so by “claiming the patronage of Apollo-Sol, Constantine distanced himself from the claims…that he was Maximian’s true son and heir,” as well as recent criticisms that he was illegitimate, born of a concubine (see Stephenson, Roman Emperor, Christian Victor, p.; see Follis depicting the head of Constantine and Sol Invictus). For Cameron and Hall, the vision of Apollo in 310 allowed Constantine to view himself in the form of Augustus, with whom Apollo had been associated (on Augustus and Constantine, see the commentaries on the Colossus of Constantine and the Life of Constantine I.39). However, in Eusebius’s narrative, the vision of Christ ought to be paralleled with that of Moses in the burning bush (Exodus 3:6), in which God reveals himself to Moses prior to his liberating the Jews from slavery in Egypt. Indeed, Moses is shown to model the Ark of the Covenant and the tabernacle on patterns shown to him by God (Exodus 25-27 and 36-39), and parallels can be noted between the Ark and Constantine’s trophy of the cross (the labarum, shown on coins from Constantinople, Trier, and Rome from 327 to 337 CE) described in the Life of Constantine I.29 (Life of Constantine, p. 305; see also Nixon and Rodgers, In Praise of Later Roman Emperors, p. 250, n. 93; on Constantine and Moses in Eusebius’s writings, see the commentary on Life of Constantine I.12).

Interpretations of Constantine’s vision/s have varied. Peter Weiss has argued that the vision of Apollo in the Latin panegyric and the vision described by Eusebius are in fact the same event interpreted differently by authors with different perspectives and agendas. Weiss explains both, however, with a somewhat far-fetched natural phenomenon known as a ‘solar halo.’ According to this theory, a solar halo occurred on a spring afternoon in 310 CE, which was manifested as two concentric circles, with the inner having three points of strong light, which might have been seen as the numeral XXX in a circle. Moreover, such solar halos can create a ‘light cross’ due to a horizontal axis passing through a ‘sun pillar.’ Weiss therefore suggested that this was what Constantine saw, and the vision was initially interpreted as predicting his thirty-year reign, but then after a dream at a later point in time, Constantine re-remembered the vision as displaying a cross of light. This has caused many to assume that the vision took place in 312, the night before the battle of the Milvian Bridge (“The Vision of Constantine”; see also his earlier “Die Vision Constantins”). Weiss has been supported recently by Timothy Barnes, but his theory has drawn criticism from Van Dam for being “reductionist” (Barnes, Dynasty, Religion and Power, p. 75; Van Dam, Remembering Constantine, p. 12, n.18).

As has been recently stated by Van Dam, Constantine’s vision has been viewed by scholars as a transformational moment for the relationship between Christianity and the Roman empire. On the surface, the episode confirmed the point at which Constantine’s conversion was secured, and thereby sped up the process of the Christianising of the empire. The subsequent effect of Constantine’s adoption of Christianity on Roman law, politics, and society more generally was undeniably significant, regardless of where one stands in the debates regarding the timescale, precise nature, and agenda of this (Remembering Constantine, p. 3-4). In terms of the events detailed in the present extract, whatever the historical circumstances, it remains the case that those who have retold the story of the emperor’s victory at the Milvian Bridge—whether the pagan author of the Latin panegyric, or the Christian authors Lactantius and Eusebius—understood divine agency, and the emperor’s recognition of this, as key to his triumph, and assurance of his legitimacy and suitability as sole ruler of the empire.