Holy War and the Kingdom of Heaven: Pope Leo IV’s Letter to the Frankish Army (847/8?)

I’ve recently had cause to think about holy war in the Carolingian period again. One of the things that struck me is that this is a subject that suffers from being in the shadow of the Crusades. This is not just because the Crusades are the archetype for medieval Christian holy wars, by which all others are measured and understood. Much of the scholarship on holy war in the Carolingian age has been carried out by Crusades specialists trying to understand how a religion of peace whose earliest practitioners were suspicious of military affairs came to be the faith of people crying out ‘Deus le volt’ as they stormed Antioch and Jerusalem in the last years of the eleventh century. The result tends to be a whistlestop tour across a millennium, hitting a couple of perennial points such as Constantine’s conversion and Augustine’s formulation of just warfare, before racing onto the next stop a couple of centuries later.

One of the old chestnuts briefly paused at is the letter of Pope Leo IV (r.847-853) to a Frankish army in the middle of the ninth century. This letter is important as possibly the first place a Christian religious authority explicitly says that soldiers who die fighting a holy war automatically go to heaven. This is of great significance for historians of the Crusades, because the concept of a papal indulgence for those who participated in the campaign is at the heart of many definitions of a Crusade. But in most scholarly accounts the letter merits half a sentence and a footnote. This is a shame, because it’s a fascinating text. Because of this neglect, and because if people on the internet are going to argue about medieval holy war they should at least have access to decent sources and I don’t think the Fordham translation is particularly good, I thought it might be useful to offer one of my own.

Leo IV, Epistolae selectae, ed. A. Hirsch-Gereuth, MGH Epp 5 (Berlin, 1899), no. 28, 601.

To the army of the Franks

1. Put aside all fear and panic, and endeavour to act manfully against the enemies of the holy faith and the foes of all lands.

2. Likewise. Up until now your forebears have always proved to be victorious when they marched forth in military array, and no multitude of people could overcome them. For we have not heard that they ever returned without the fame of a victory.

3. Likewise. Beloved, we want all of you to know that whoever dies faithfully in this contest of war (which we say not wishing it comes to pass) will by no means be denied the kingdom of heaven. For the Almighty knows that if any of you die, he died for the truth of the faith and the salvation of the soul and the defence of the country of Christians, and therefore he will obtain the aforesaid prize [i.e. heaven] from Him.

An important thing to note about this letter is that it only survives in later legal collections. The full text is preserved in a manuscript known as the Collectio Britannica (BL Add MS 8873 f.167v) which contains a collection of canons probably assembled in France in 1108. The canonist Ivo of Chartres (d. 1114) included it in his Decretum (X.87) and in slightly shortened form in his Panormia (VIII.30). An abbreviated version of Leo’s letter, attributing it to the more celebrated Pope Nicholas I (r. 858-867) makes an appearance in Gratian’s Decretum (C. 23 q. 8 c. 9). The letter survived because it was used as a legal precedent, but this means we don’t have any sense of context for when it was written, who exactly Leo was addressing or how it circulated before the late-eleventh century (i.e. when the Crusades began), although the Collectio claims to be drawing the letters from Leo’s Papal Register. The conventional date of 853 assigned to the letter has no particular evidence behind it and is not to be trusted, particularly as there was no Frankish army near Rome in that year.

We can say a little more about the context of Leo’s pontificate. It was defined by an event that took place the year before he was elected, when in August 846 a Saracen raiding party sacked the part of Rome that lay outside the Aurelian walls, including the basilicas of Old St Peter’s and San Paolo fuori le Mura. As Pope, Leo responded to this disaster by repairing the basilicas, fixing the city walls and establishing a new set of fortifications, known as the Leonine Walls, which contain what is now the Vatican City. Knowing that the raiders might return, he also sought to mobilise aid from the Carolingian rulers of Italy, Emperor Lothar I (r. 817-855) and his son Louis II (r. 844-875), and from southern Italian cities such as Naples, Gaeta and Amalfi. This preparation paid off when a Christian naval coalition intercepted and defeated a Saracen fleet heading towards Rome at the Battle of Ostia in 849. Despite this success, the sack of 846 was an immensely traumatic moment, which sent shockwaves across Christian Europe and threw Rome into a state of emergency. Although we know that the Eternal City would remain safe from the Saracens from then on, Leo obviously didn’t. In 847 Saracen pirates took over Bari, establishing an Emirate that would raid into southern Italy for the next two-and-a-half decades. This atmosphere of crisis helps to explain the unusual contents of the letter.

Raphael’s depiction of The Battle of Ostia in the Apostolic Palace in the Vatican, painted in 1514-15. Note Leo IV on the left, bearing a strong resemblance to Pope Leo X (r.1513-1521).

Although Leo specifies that the Frankish army is fighting against enemies of the faith in c.1, the discussion of holy war is mostly confined to c.3, where it is pretty explicit. Franks who die righteously in this war will go to heaven. Leo lays stress on the causes they are defending – the truth of the faith, their souls, and the defence of Christendom. It’s hard to find much in the way of precedent for this statement. This is surprising given how many of the elements that made it were already available. Paul compared Christians to soldiers fighting for the cause. Christian martyrs had been dying for the faith from the very beginning, and they automatically won eternal life for doing so. As I have discussed elsewhere, Charlemagne waged wars that were meant to bring Christianity to new peoples such as the Saxons, or to rescue Christians believed to be suffering persecution in the Iberian Peninsula. Bringing together the ideas of fighting for the faith and going to heaven for dying for the faith seems like an obvious thing to do.

Pope Leo’s letter is perhaps not as isolated as it may appear. Many of the papal letters preserved in the Codex Epistolaris Carolinus on Charlemagne’s orders in 791 contain suggestions that going to war on behalf of the pope could ensure one’s path to heaven. A particularly striking example appears in a letter of 756 sent by Pope Stephen II (r. 752-757) to King Pippin III (r. 751-768) and his sons, which purports to be the words of St Peter addressing the Franks. Stephen wanted Frankish help against the Lombard king Aistulf (r. 749-756). St Peter lists the crimes of the Lombards to the Franks before stating that he was:

Offering you the rewards of eternal recompense and the unending joys of heaven – provided that you have very speedily defended my Roman city and my own people, your Roman brothers, from the hands of the evil Lombards.

(Translated in McKitterick, van Espelo, Pollard and Price.)

There are some obvious differences with Leo’s letter. Peter/Stephen doesn’t state that the Franks would have to perish while on this campaign to enjoy this heavenly perk. More surprising is the target of this campaign, the Lombards being Christian, albeit not behaving particularly so from a papal perspective.

Despite these differences, this letter and others in the same collection offer a Carolingian context for Pope Leo’s exhortation to the Frankish army. Something similar appears in material celebrating Gerold, the Prefect of Bavaria, who died fighting the Avars in 799. Heito’s Visio Wettini from 824 declared that Gerold deserved ‘everlasting life’ because he died ‘in defence of the holy church against the infidels’. Fraser recently drew my attention to a sermon of Abbo of Saint-Germain from the 880s, translated by Charles West, which calls upon the listener:

Do not let your enemies multiply and grow but, as Scripture commends, fight for your homeland (patria), do not fear to die in God’s war (bellum Dei). Certainly if you die there, you will be holy martyrs.

I suspect that such ideas were not unknown elsewhere in the Carolingian world, but they might not have been commonly expressed. This is hinted by the fact that in 878 Pope John VIII (r. 872-882) had to reassure the bishops of the West Frankish kingdom that those who died fighting against pagans would go to heaven, suggesting that it wasn’t an idea that they regularly encountered. Likewise, the importance of Leo’s letter for the canonists was in large part the result of the absence of other authorities to draw upon. When Peter Comestor (d. 1179) sought to defend the point in a tract addressed to a Patriarch of Jerusalem, his only sources were Leo and Pope Urban II (r. 1088-1099).

Looking at c.3 of the letter alone makes Leo IV look like a solitary prophet of the age of the Crusades. The rest of the text however very firmly places him in the Carolingian world. This is a letter written by Leo to stiffen the spine of a Frankish army, and the consolations of heaven to the fallen is the very last argument he uses to steady the troops. He begins by emphasising the evil of the enemy, who are both inimical to the faith and the peace of all people (c.1). Interestingly, Leo addresses the men in the context of the history of the Franks in c.2, recalling to them the example set by their ancestors. In doing so, the Pope was probably doing more than reminding them of the formidable achievements of Frankish arms over the previous century and a half. He also implicitly harked back to the relationship between the Carolingians and the Papacy that stretched back to the days of Pippin and Stephen, in which the Franks protected Rome against all threats. The sack of 846 was a shocking moment for the Carolingians as well as the Papacy, prompting Lothar and, particularly, Louis II to pay much more attention to southern Italy. The latter would define his reign by his capacity to protect Italy and the Pope from Saracen threats. That bond was acknowledged by Leo as he steeled the Franks of his own day by celebrating the deeds of those long past.  

This may give us a clue for dating the letter. Louis II arrived in southern Italy with a Frankish army in 847, and spent much of 848 campaigning against Muslim pirates while trying to end the civil war that had riven Benevento, leading to the formal division in 849 of the troubled principality. He returned south in 852 to campaign against Bari. This suggests 847-8 or 852 as the most likely contexts for the Leo’s address to a Frankish army. Although it could be either, I’m tempted to go with the earlier date, simply because praising the efforts of the ancestors of the Frankish army seems like a slightly odd move if there had already been an expedition five years earlier in which some of the army of 852 had probably participated. By contrast, before 847 there hadn’t been a Frankish army south of Rome since the days of Charlemagne, a full generation earlier.

Even if we can’t pinpoint the exact year of the letter, we can locate it in a Carolingian milieu. Leo’s comments on the souls of those fallen in holy war were unusual for his period. They would go onto be highly influential in the very different circumstances of the Crusades. But by reading the entire letter as it survives to us, we can see it as the product of the Carolingian world, written not to be an example for lawyers, but as a rallying cry for desperately scared and fiercely proud men in a time of crisis.

One thought on “Holy War and the Kingdom of Heaven: Pope Leo IV’s Letter to the Frankish Army (847/8?)

Leave a comment