Among the projects I’ve been working on recently is an introduction to Carolingian diplomacy for an edited volume on late antique diplomacy (the publication date is a long way off so more details closer to then). Writing for an audience interested in diplomacy from this period, but unfamiliar with the Carolingians has been a useful exercise, prompting some interesting questions. One of which is, what was distinctive about Carolingian diplomacy? What would look unusual to someone used to Byzantium or Tang China?
This is a slightly different proposition to thinking about what defined Carolingian diplomacy. For example, I would argue that the main ideological objectives of Charlemagne’s foreign policy, apart from naked self-aggrandisement and survival, would be promoting the prestige of the Frankish people, protecting the Christian faith, and claiming the legacy of the Roman empire. Any attempt to seriously think about the subject needs to consider how these elements played into the motivations for and presentation of Carolingian diplomacy. But while that’s a potent ideological brew, it’s not necessarily a unique one. If we substitute ‘Roman people’ for ‘Frankish people’ we would find a similar concoction being supped in the palaces of Constantinople. Indeed, ‘large political entity that elevates the ruling ethnic group, promotes a universal faith, and looks to a previous empire as a model’ is a label that works for most of the great powers of late antiquity.
For me, most of the things that are distinctive about Carolingian diplomacy emerge out of the institutions of the empire. Polities tend to conduct diplomacy in the same way they organise other activities and the Franks were no exception. I think one of the first things that might surprise my hypothetical specialist from another field is how barebones the organisation of Carolingian diplomacy is, even by the standards of premodern empires. There’s no official with responsibility for handling external affairs, such as the Byzantine logethetes tou dromou, or body of professional bureaucrats such as the secretaries employed by the caliphs. The type of handbooks we find in those empires advising rulers on the practicalities of foreign policy are also absent. The Franks were no strangers to paperwork, but it’s hard to see an equivalent to the deep archives recording previous encounters that we can glimpse in Constantinople or Baghdad. When Charlemagne assembled earlier papal correspondence into one collection in 791, it appears to have been something of a novelty.
This didn’t make Carolingian diplomacy unsophisticated or ineffective, but it meant it was shaped by the nature of the empire it served, an entity with a strictly limited state apparatus. One of the obvious places this appears is in the envoys dispatched by Frankish rulers to foreign courts. Carolingian government often worked through missi, powerful individuals such as counts or bishops appointed on a temporary basis to investigate specific problems or carry out particular tasks within the empire. Frankish monarchs used the same institution to send envoys to foreign rulers, with missi acting as diplomats. These were normally the same sort of people who carried out the office internally, bishops, abbots and counts.
Like their domestic counterparts, missi working as envoys were appointed for one defined exercise. We rarely find individuals conducting multiple diplomatic missions. The expertise on these embassies generally came from their support staff, who would be more familiar with their destination. Many of these harder-to-see individuals were merchants or inhabitants of the frontier with knowledge of routes and languages. What was important about the missi was that they were trusted by their monarch and high enough in status to convey the seriousness of their errand.
Another distinctive feature is the role of the assembly (discussed by my editor here and here). Frankish kings normally held assemblies on at least an annual basis. In the absence of a permanent capital (Charlemagne’s Aachen being very much the exception rather than the rule), these took place in a number of different central cities or palaces. They could also be held close to the frontier if warfare was anticipated. These moving assemblies allowed the Carolingians to meet with elites from different parts of their empire, get a sense of their mood, and solidify the political community. Ceremonies, grants, and legal cases took place here, where the king could be openly seen to fulfil their duties.

It was at these assemblies that foreign envoys were often received and their message and the appropriate response discussed. This allowed the Carolingians to display their visitors before their gathered nobles, adding to their prestige as they publicly conducted statecraft. This had consequences for the practice of diplomacy. The mobile nature of Carolingian government meant it wasn’t always obvious where legates should travel to. It also created a curious diplomatic rhythm. Foreign missions might have to put up with kicking their heels before being dragged across western Europe to an assembly before they could formally perform their mission, to the annoyance of their masters back home. The extent to which the assembly was actually making decisions about foreign policy was probably limited, but it did offer a gauge of general sentiment. Charlemagne praised the Byzantine Arsafius for his skill at working elite opinion towards accepting a treaty.
One feature with very obvious implications was the Frankish habit of dividing their lands among their throne-worthy sons, something unusual among the great powers of Western Eurasia. The tendency of Carolingian kingdoms to separate and merge at unpredictable intervals complicated the development of permanent institutions. It also meant that a substantial quantity of Carolingian diplomacy was conducted between members of the dynasty. This amoeba-like behaviour gave neighbouring powers opportunities to play rival Frankish kings against each other, but they also had to risk the rapidly changing kaleidoscope of the Carolingian political landscape disrupting all their plans.
The Frankish relationship with the Pope also strikes me as distinctive. For the emperor in Constantinople the bishop of Rome was just one religious authority among many, albeit an unusually unruly one with great influence in the west. For the Carolingians, the pope was central to their story about who they were. Both Pippin the Short’s royal consecration in 754 and Charlemagne’s imperial coronation in 800 took place in the context of protecting the pope. Defending Rome was a major part of their self-justification, which was why the sack of the city in 846 was a catastrophe for Lothar I, on whose watch it had happened. The pope also offered resources and guidance for the correct conduct of Christianity, another essential plank of the Carolingian project. The prayers of every priest and monk in Rome went to strengthening Frankish armies on the march.
At the same time, the pope was extremely vulnerable to Carolingian pressure. Unlike the likes of Gregory VII in the eleventh century, pontiffs between c. 750-875 were effectively choosing between various flavours of the same family as protector, giving them limited options to manoeuvre. This had consequences for Carolingian diplomacy. First, there was the unique relationship between Frankish rulers in this period and the popes. Second, the need to protect Rome kept the Carolingians invested in maintaining a stable southern Italy. Third, pontiff and king often cooperated in each other’s promotion of Christianity overseas, making their efforts hard to disentangle.
There’s one final feature that I’d like to mention that manifests more as an attitude than anything else, which is the intense curiosity of the Carolingians about the outside world. Einhard tells us that Charlemagne loved having foreigners around and his reign certainly seems to bear that out, featuring headliners like Alcuin of York and the Gothic Theodulf, but also a larger cast of people from the edges of the empire and beyond. That didn’t always play well with Frankish elites, as the response to Louis the Pious dressing like a Vascon or Charles the Bald garbing himself like a Byzantine emperor showed. But as a rule, the Carolingians themselves do seem to be genuinely interested in the wider world. You can almost sense Louis the Pious’ excitement at the novelty of Bulgar envoys in 824 or Rus’ visitors in 839. (Both of these get complicated in different ways).
This outward-looking attitude plays out in a number of ways. I suspect the keenness of the Carolingians made it less of a problem that there was a limited permanent diplomatic infrastructure around. When the guy at the top consistently pays attention to foreign affairs things are going to happen even without an extended bureaucracy. More broadly, it meant there was only a small appetite for an isolationist policy. The Carolingians were always going to be involved in the concerns of the wider world. From a modern perspective such cosmopolitanism might seem like a positive attribute, but many of the neighbours of the Franks might wish they were rather more aloof. Those same instincts motivated extensive meddling in the affairs of other powers. The empire reached out constantly, testing the waters and probing for opportunity. The Carolingians were always interested in gathering shiny objects but less concerned with the condition of their former owners.
Ideas of rulership shaped this dynamic. Frankish kings were supposed to be war leaders in a way that caliphs or Byzantine emperors were not. Their armies were accustomed to being led by members of the Carolingian family. They were also meant to bring the world to the Franks, as demonstrated by a certain elephant arriving in Aachen. Even in the ninth century, after the pace of military expansion had slowed, Carolingians were expected to be extending Frankish influence. That supported an aggressive approach to the outside world, even if it didn’t always involve the application of direct force.
These stray thoughts don’t amount to a comprehensive definition of Carolingian diplomacy. It’s probably not even a full list of all its distinctive features. But I think it captures something of the flavour of it. Much of the way the Carolingians conducted diplomacy comes downstream of the same way they did everything else. The type of people carrying out diplomatic missions were the same as the ones carrying out every other sort of mission. Big diplomatic moments happened at assemblies because that’s where all the other big moments took place. But the expectations of and ideological commitments made by the dynasty also played a big part. The Carolingians made the pope a keystone of their legitimacy, and that shaped their relationship with him and the wider world. The Carolingians were expected to extend Frankish power, and to demonstrate that before the watching political community, and that also had consequences for they approached diplomacy.
Exercises like this are helpful for clarifying what’s unusual about the subject you study and prompting you to consider how those striking features came about. It’s one of the reasons it’s really important as a historian to try to work with scholars doing similar things to you in different places, because the perspective it provides gives a much better understanding of your own subject. Much like the Carolingians, we also benefit from looking beyond our borders (although hopefully in a manner featuring fewer corpses).








