When rain saved the Thundering Legion ~ Legio XII ~ during the Macromannic Wars of Marcus Aurelius

The Miracle of the Rain as depicted on the Column of Marcus Aurelius in Rome.

While researching something completely different, I recently stumbled across the fascinating story of a miraculous cloudburst which saved part of the Roman army during Marcus Aurelius's Macromannic campaign, circa AD 174. It is an intriguing piece of Roman history with numerous and varied ancient sources corroborating it. I was surprised to discover that the story had been exhaustively studied by scholars over the centuries, with at least one full-blown monograph dedicated to it in recent times.

The Macromanni were a Germanic tribal confederation which pierced the Roman frontier in the mid-160s and devastated a swath of the empire from the Danube reaching nearly to the Adriatic coast. In reaction to this invasion, Marcus Aurelius mustered numerous legions from across the empire and began a campaign to push the invaders out and reconfigure the defensive scheme in the region. The war became a complex series of thrust, retreat and counter-thrust lasting over ten years and consuming much of Aurelius's reign.

The miracle of the rain occurred late in the war, probably during the campaign across the Danube to subdue the Quadi, one of the chief tribes of the Macromanni. At one point, a segment of the Roman army including the 12th Legion, also known as the "Fulminata" or Thunderbolt, seems to have been cut off by a large force of Quadi. The Roman historian, Cassius Dio writing about 50 years after the event, described the situation as follows:

The Quadi had surrounded them at a spot favorable for their purpose and the Romans were fighting valiantly with their shields locked together; then the barbarians ceased fighting, expecting to capture them easily as the result of the heat and their thirst. So they posted guards all about and hemmed them in to prevent their getting water anywhere; for the barbarians were far superior in numbers. The Romans, accordingly, were in a terrible plight from fatigue, wounds, the heat of the sun, and thirst, and so could neither fight nor retreat, but were standing at the line and at their several posts, scorched by the heat... [Cassius Dio's quotes are taken from here: Dio on the Rain Miracle.]

The legion, however, was saved by a timely and intense cloudburst:

Suddenly many clouds gathered and a mighty rain, not without divine interposition, burst upon them...At first all turned their faces upwards and received the water in their mouths; then some held out their shields and some their helmets to catch it, and they not only took deep draughts themselves but also gave their horses to drink. And when the barbarians now charged upon them, they drank and fought at the same time; and some, becoming wounded, actually gulped down the blood that flowed into their helmets, along with the water. So intent, indeed, were most of them on drinking that they would have suffered severely from the enemy's onset, had not a violent hail-storm and numerous thunderbolts fallen upon the ranks of the foe.

This much, at least, historians seem to agree upon. Dio's description above is largely accepted, even though this excerpt comes not from the surviving manuscripts of his Roman History, which is partially lost, but from the works of a later Byzantine historian, Xiphilinus. Things get more confused when the miraculous aspects of this event are considered.

Xiphilinus includes Dio's opinion that the rain was of divine origin:

There is a story to the effect that Harnuphis, an Egyptian magician, who was a companion of Marcus, had invoked by means of enchantments various deities and in particular Mercury, the god of the air, and by this means attracted the rain.

This view is supported in a most unusual and unmistakable way by physical evidence from the Column of Marcus Aurelius in Rome (see detail above), which clearly depicts a divinity of some sort pouring down rain and bringing succor to the Roman soldiers and their beasts.

Christians of roughly the same time period, however, had a different spin on the story. Writing a few years after the miracle, Apollinaris of Hierapolis recorded the event as follows, according to a paraphrase from the great Church History of Eusebius Pamphilus:

Bust of a young Marcus Aurelius
from the British Museum.

There is a story about … the emperor Marcus Aurelius when he faced the Germans and Sarmatians. His army was tormented by thirst and he was in dire straits. The soldiers of the so-called Melitenian Legion, which was and still is strengthened by the faith, knelt on the earth in battle order before the foe, as is our custom when we pray, and turned to God with their supplication. While such a display caused the enemy to wonder, at the same time, the story goes, an even greater miracle took place: a thunderstorm put the enemy to flight and destruction, while the rain brought refreshment to the army of those who had called upon the divine, although it was almost perishing with thirst....Ever since that time, the legion that brought about the miracle through their prayers received from the emperor an appropriate epithet and has been called the “Hurling of Thunderbolts” in the language of the Romans. [Taken from Huttner: Early Christianity in the Lycus Valley, p. 232-3.]

Though Apollinaris (or Eusebius) seems to get a key detail wrong—Legio XII had had the epithet "Fulminata" since at least the time of Augustus—his account basically agrees with that of Dio. Tertullian, writing about 20-30 years before Dio, also records the same incident, giving it a similar Christian spin, but adding another detail:

We, however, can on the other side produce a protector, if the letters of the most grave Emperor Marcus Aurelius be searched, in which he testifies that the well-known Germanic drought was dispelled by the shower obtained through the prayers of Christians who happened to be in the army. And although he did not openly abolish the penalty incurred by members of that sect, yet in another way he openly averted it by the addition of a condemnatory sentence on the accusers, and that a more terrible one. [Taken from Kovac: Marcus Aureliusa Rain Miracle and the Marcomannic Wars, p. 23]

Most interesting of all, a document purporting to be this same letter cited by Tertullian above, actually exists to this day. Unfortunately, most scholars consider this epistle—which may be found appended at the end of the First Apology of Justin Martyr though it has no relation to it—to be an interpolation by a later Christian writer, or else an outright fabrication. Whatever it is, its provenance is clearly quite ancient. Here it is in full:

The Emperor Cæsar Marcus Aurelius Antoninus, Germanicus, Parthicus, Sarmaticus, to the People of Rome, and to the sacred Senate greeting: 

I explained to you my grand design, and what advantages I gained on the confines of Germany, with much labor and suffering, in consequence of the circumstance that I was surrounded by the enemy; I myself being shut up in Carnuntum by seventy-four cohorts, nine miles off. And the enemy being at hand, the scouts pointed out to us, and our general Pompeianus showed us that there was close on us a mass of a mixed multitude of 977,000 men, which indeed we saw; and I was shut up by this vast host, having with me only a battalion composed of the first, tenth, double and marine legions. 

Having then examined my own position, and my host, with respect to the vast mass of barbarians and of the enemy, I quickly betook myself to prayer to the gods of my country. But being disregarded by them, I summoned those who among us go by the name of Christians. And having made inquiry, I discovered a great number and vast host of them, and raged against them, which was by no means becoming; for afterwards I learned their power. Wherefore they began the battle, not by preparing weapons, nor arms, nor bugles; for such preparation is hateful to them, on account of the God they bear about in their conscience. Therefore it is probable that those whom we suppose to be atheists, have God as their ruling power entrenched in their conscience. For having cast themselves on the ground, they prayed not only for me, but also for the whole army as it stood, that they might be delivered from the present thirst and famine. For during five days we had got no water, because there was none; for we were in the heart of Germany, and in the enemy's territory. And simultaneously with their casting themselves on the ground, and praying to God (a God of whom I am ignorant), water poured from heaven, upon us most refreshingly cool, but upon the enemies of Rome a withering hail. And immediately we recognized the presence of God following on the prayer — a God unconquerable and indestructible.

Founding upon this, then, let us pardon such as are Christians, lest they pray for and obtain such a weapon against ourselves. And I counsel that no such person be accused on the ground of his being a Christian. But if any one be found laying to the charge of a Christian that he is a Christian, I desire that it be made manifest that he who is accused as a Christian, and acknowledges that he is one, is accused of nothing else than only this, that he is a Christian; but that he who arraigns him be burned alive. And I further desire, that he who is entrusted with the government of the province shall not compel the Christian, who confesses and certifies such a matter, to retract; neither shall he commit him. And I desire that these things be confirmed by a decree of the Senate. And I command this my edict to be published in the Forum of Trajan, in order that it may be read. The prefect Vitrasius Pollio will see that it be transmitted to all the provinces round about, and that no one who wishes to make use of or to possess it be hindered from obtaining a copy from the document I now publish. [Taken from: Epistle of Marcus Aurelius to the senate, in which he testifies that the Christians were the cause of his victory.]

Problems with this document are evident to anyone with even the modicum of familiarity with the history and personalities of the time period. The most obvious issue is that Aurelius himself was considered a persecutor by later Christians, and is often implicated in the severe campaign against the Christians in southern Gaul which took place in AD 177. It is argued that an emperor who looked so favorably upon the Christian God, would be unlikely to embark on such a campaign of eradication a mere three years later.

For an in-depth analysis of this document, see Peter Kovac's book, Marcus Aurelius's Rain Miracle and the Macromannic Wars which is a tour-de-force on this fascinating topic.

Kovac posits that the above letter was written in the early 4th century AD. It is supposed by others that the letter's purpose was to stand in for the authentic epistle of Aurelius mentioned by Tertullian which theoretically had been lost by the time Christians had gained access to the Imperial archives after Constantine. Possibly, the original epistle was destroyed during the persecution of Diocletian when many works of Christian literature were burned.

Regardless of the dispute over the sources, at least two intriguing facts can be gleaned from this episode: 1.) the number of Christians serving in the Roman army by the late 2nd century was not insignificant; and 2.) some sort of extraordinary celestial event did indeed happen which saved part of the Roman army during the Macromannic War.