Union between the Holy Roman Empire (HRE) and the Eastern Roman Empire (ERE).

[LNSS]

A map:

Basically, what would be a suitable PoD for the enterity of Charlemagne's empire, the green in the map that composes most of continental christian europe, to be united with the Eastern Roman Empire, all under a single monarch. The united Rome should remain united for at least five centuries or so.

While it might not seem extremely plausible, I got this idea into my head about a united Roman Empire spanning the entire mediterranean, but very decentralized and feudal in nature (like the HRE somewhat), and extremely multicultural. There would be greeks in Greece and Anatolia, Lombards in Lombardia, Franks in Francia and Germans in Germany, etc. but all owing fealty to one Emperor. Feudalism could probably make such a big empire work. Probably. Maybe. Hopefully.

Most importantly, how would it change history if this (non-)super entity survived to the Modern Era. For example, France and germany would not have developed, England is probably never invaded by Rome again, IDK about Iberia, but what abouy Islam and the Americas?

 

[Thespitron 6000]

If we do not call the result the Holy Eastern Roman Empire (HERE), I will be very disappointed.

 

[Evan]

The excuse the Pope gave for crowning Charlemagne as Emperor - despite everyone taking it for granted that there was a single Imperial crown - is that the Imperial crown in Byzantium had fallen into the hands of a woman, Empress Irene. Of course, the Byzantines objected to this. Charlemagne helpfully tried to solve the problem by proposing marriage to Irene.

Unfortunately, before she could answer his letter, she was overthrown in a palace coup. But, what if she accepts? It's very unlikely, but perhaps she escapes the coup and desperately tries to find a refuge for herself or at least some support even if it's foreign? That could technically merge the two empires and provide the impetus for a later, more real merger.

 

[Richthofen]

The excuse the Pope gave for crowning Charlemagne as Emperor - despite everyone taking it for granted that there was a single Imperial crown - is that the Imperial crown in Byzantium had fallen into the hands of a woman, Empress Irene. Of course, the Byzantines objected to this. Charlemagne helpfully tried to solve the problem by proposing marriage to Irene.

It was also the fact that she usurped the throne from her son after blinding him and killing him in the process. Basically, her legitimacy was nonexistent in the eyes of pretty much everyone. I bet the Pope saw that as an opportunity of a lifetime to finally "remove" the Imperial Crown from the heretics in Constantinople. And it all paved the way for the Great Schism three centuries later which is why I believe a merger of the two Empires is borderline impossible, you'd pretty much have to also reconcile Western and Eastern Christianity for that to happen.

 

[LtNOWIS]

Yeah, at this stage the Christian doctrinal differences between the East and West were effectively unresolvable. Also the Byzantine administrative apparatus was pretty in-depth, while nothing of the sort existed in Western/Central Europe.

 

[Elfwine]

Heretics? Um, no. Both East and West are on speaking terms in that regard at the moment (the 800s).

There's friction, but hardly anything unresolvable or unmanageable or to the point of deeming one side "heretical".

Let's not project attitudes from the 13th century back to the 9th.

Culturally, however, what self-respecting Roman (Byzantine) is going to accept rule by a barbarian? Which, to their eyes, Charlemagne most definitely is - even as a fellow Christian. A comparison I read goes - from memory - of it Irene marrying Charlemagne being seen like Vienna would see Maria Theresa marrying the negus of Ethiopia.


Also, even if somehow an individual is accepted as both Western and Eastern Emperor, the ERE is not a hereditary monarch. The father being accepted is a poor guarantee of the son being so, especially in cases like this. Add in that Frankish inheritance is done by gavelkind, and this won't last - it'd be almost inevitable one half (at best) goes to one son and the other to another even without usurpers and coups.

 

[Richthofen]

Heretics? Um, no. Both East and West are on speaking terms in that regard at the moment (the 800s).

There's friction, but hardly anything unresolvable or unmanageable or to the point of deeming one side "heretical".

Granted, I might have exaggerated a bit with the word "heretic", but still, Christianity was divided (I'd say even insurmountably divided at this point) even if formally there was one church.

Agreed on the cultural differences, though.

 

[Lucius Cornelius Sulla]

Culturally, however, what self-respecting Roman (Byzantine) is going to accept rule by a barbarian? Which, to their eyes, Charlemagne most definitely is - even as a fellow Christian. A comparison I read goes - from memory - of it Irene marrying Charlemagne being seen like Vienna would see Maria Theresa marrying the negus of Ethiopia.

And yet Basil I started life as a slave, and Zeno was an Isaurian barbarian, there was an entire dynasty of Isaurians, Justin was a peasant and swineherd, Tiberius III was a German (hey! Just like Charlemagne!). I could go on and on.

I'm not saying you're not correct, just that those Greeks were so hypocritical it's not even funny. Still, maybe Charlemagne's intelligence and physical impressiveness will act to counter his "barbarian" status.

 

[Elfwine]

Granted, I might have exaggerated a bit with the word "heretic", but still, Christianity was divided (I'd say even insurmountably divided at this point) even if formally there was one church.

More than a bit. I'm not going to say everything was love and brotherhood, but presenting the 9th century Church as "insurmountably divided" would surprise most of the people there.

And yet Basil I started life as a slave, and Zeno was an Isaurian barbarian, there was an entire dynasty of Isaurians, Justin was a peasant and swineherd, Tiberius III was a German (hey! Just like Charlemagne!). I could go on and on.

Basil spoke (thickly accented) Greek. I'm not sure on Zeno, but the Isaurian dynasty was also at this point at least able to pass for Greco-Roman. Justin - see Basil. Tiberius III is probably the same as the Isaurian dynasty - able to pass for Roman.

I can go on and on too. Just because to our eyes Charlemagne was further removed from "barbarism" (which tends to be used less as a matter of "merely" wrong culture and more about "primitive"/"savage" these days) doesn't mean he was to theirs.

I'm not saying you're not correct, just that those Greeks were so hypocritical it's not even funny. Still maybe Charlemagne's intelligence and physical impressiveness will act to counter his "barbarian" status.

I would hate to argue Byzantium wasn't hypocritical at times - Byzantium wallowed in hypocritical self-righteousness as badly as Perfidious Albion - but they're entirely consistent in declaring Charlemagne a barbarian.

His intelligence really has nothing to do with it, and his physical impressiveness no more relevant.

To put it simply, its like the US idea that the president has to be a native born citizen - the "not"s are that no matter how awesome.

And I don't see Charlemagne agreeing to act like a "Greek".

 

[SlyDessertFox]

It is to my understanding that Zeno was...not the most well liked of emperors to put it mildly.

 

[FellowNerd]

If if that went through that empire would be such an unrulably mess with out the governing institutions of the Romans, the mixing of laws (Particularly succession) and the conflicting cultures. Even if it did happen I can see it breaking apart in less than a generation.

 

[DominusNovus]

The religious differences were greatly exaggerated in this particular period; the Photian Schism, which was not based in doctrine at all, did not even occur for another half century. To say the division was already inevitable would be like saying the same of the Avignon Schism. Or, to use a less applicable analogy of which I am particularly fond (someone on here back in the good ol' days used it): World War I was as inevitable as World War III.

Anyway, there's some possibility that Charlemagne did not want to be crowned Emperor in the first place; though any such story always has the possibility of being a 'reluctantly accepting the crown' PR ploy, in the vein of... well, every founder of a new monarchy in history. Regardless of the truth, we needn't presume that a unification would require absolute legal equality.

Suppose that the betrothal of Constantine VI (Irene's son) and Rotrude (Charlemagne's daughter) goes through. This won't unify the Empires, of course, since Salic Law demands inheritance through the male line only. However, it does bind their fates closer together.

Lets be nice to the newly wed couple and presume that Rotrude gives birth to a healthy young son, likely named Leo. Now, Constantine won't have as much reason to get involved in all the problems that got him killed. Without Constantine dead, the Pope won't have much reason to go trying to crown his own Emperor, and Charlemagne isn't all that likely to try to usurp the crown of his son-in-law (Carolingian propaganda, historically, stated that Charlemagne was Constantine VI's successor).

Without assuming anyone important over in Greater Francia dies out of order, we have two powerful realms tied by a dynastic alliance, one ruled by an Emperor, and one by a very powerful King, who happens to be a great patron of the arts and learning. At a minimum, I certainly can imagine the Byzantines sponsoring the Carolingian Renaissance eagerly.

There's plenty of different interesting results (not all mutually exclusive) I can imagine from this point:
- Charlemagne is succeeded by Louis, as historically, or, other sons actually survive long enough to rule some portion of the Frankish realm. Either way, once things start getting divided up, perhaps, formally speaking, the newly divided kings are nominally established as federate kings, like the Ostro- and Visigoths of old, with the Byzantine Emperor acting as a sort of arbiter to ensure some peace. Eastern control over the West is little more than nominal, but the Varangians (I know, they're still a little ways off) and Cataphracts are a looming threat to anyone who tries to upset the balance of power)
- Constantine proves to be cruel and unpopular as historically, but any revolts against him also risk drawing the attention of the Franks. Perhaps he's driven out of Constantinople and Charlemagne, rather than becoming his supposed successor, is his benefactor, marching on the Second Rome to put his son-in-law (and, of course, eventually, grandson) back on the throne.
- The Byzantines, to help solidify the alliance, grant Charlemagne and his successors the Western Regalia officially, thus solidifying Eastern Recognition of the HRE-analogue. History proceeds roughly the same, with simply closer ties and less acrimony between the two powers.
- At some point, a Frankish ruler (perhaps as early as Louis) marries a nice Porphyrogenita, and decides to put his son on the Byzantine throne. Could make for a very interesting war, particularly depending on how relations are with the rest of the Frankish kings (presuming Charlemagne's 'Empire' is already divided up). You could see West Francia allying with the Byzantine claimant to fight the East Francian claimant, in order to keep the balance in the West.

 

[Elfwine]

Without assuming anyone important over in Greater Francia dies out of order, we have two powerful realms tied by a dynastic alliance, one ruled by an Emperor, and one by a very powerful King, who happens to be a great patron of the arts and learning. At a minimum, I certainly can imagine the Byzantines sponsoring the Carolingian Renaissance eagerly.

I'm not sure, but for discussion's sake I'm going to look at the outcomes.

There's plenty of different interesting results (not all mutually exclusive) I can imagine from this point:
- Charlemagne is succeeded by Louis, as historically, or, other sons actually survive long enough to rule some portion of the Frankish realm. Either way, once things start getting divided up, perhaps, formally speaking, the newly divided kings are nominally established as federate kings, like the Ostro- and Visigoths of old, with the Byzantine Emperor acting as a sort of arbiter to ensure some peace. Eastern control over the West is little more than nominal, but the Varangians (I know, they're still a little ways off) and Cataphracts are a looming threat to anyone who tries to upset the balance of power)

Byzantium has a lot on its plate in the 9th century. Its not really in a position to be a looming threat to quarreling Franks.

- Constantine proves to be cruel and unpopular as historically, but any revolts against him also risk drawing the attention of the Franks. Perhaps he's driven out of Constantinople and Charlemagne, rather than becoming his supposed successor, is his benefactor, marching on the Second Rome to put his son-in-law (and, of course, eventually, grandson) back on the throne.

And this would be an equally major operation for Charlemagne. Maybe even less practical.

- The Byzantines, to help solidify the alliance, grant Charlemagne and his successors the Western Regalia officially, thus solidifying Eastern Recognition of the HRE-analogue. History proceeds roughly the same, with simply closer ties and less acrimony between the two powers.

Why would they even want to?

- At some point, a Frankish ruler (perhaps as early as Louis) marries a nice Porphyrogenita, and decides to put his son on the Byzantine throne. Could make for a very interesting war, particularly depending on how relations are with the rest of the Frankish kings (presuming Charlemagne's 'Empire' is already divided up). You could see West Francia allying with the Byzantine claimant to fight the East Francian claimant, in order to keep the balance in the West.

That would be . . . interesting. But the logistical concerns involved seem to doom anyone trying to do it without serious internal support.

 

[Emperor Constantine]

Well I'm not sure if such a union between Charlemagne's Empire and the ERE was reasonable. The best opportunity of a union between the HRE (not necessarily Charlemagne's empire) and the ERE would be to have Otto III live and marry Zoe Porphyrogenita. Zoe would be the oldest niece of Emperor Basil II and the logical eventual heiress. Though logistically I'm honestly not sure HOW this empire would work. I mean where would it be governed from? Constantinople? Paris? Aachen? Even Rome? How would the Emperor be able to be on hand to deal with the various problems? Would a brother or a son be made Caesar of some of the Empire, empowered to act in the Emperor's name? To be honest, I'm not sure if a union would be functionable.

 

[DominusNovus]

I'm not sure, but for discussion's sake I'm going to look at the outcomes.

Whats not sure? Is Constantinople really that starved for artisans that they can't throw some to Aachen as window dressing on their new alliance?

PS, regarding the overall logistical concerns of a combined Empire, may we remember that, aside from trans-rhenish Germany, all this territory was, for several centuries, ruled by one government (the same government we're proposing rule the thing in this scenario).

 

[Elfwine]

Whats not sure? Is Constantinople really that starved for artisans that they can't throw some to Aachen as window dressing on their new alliance?

I'm not sure Constantinople would want to throw some on Aachen. Charles gains considerably more from Byzantine support for him being the New Roman Emperor (of the West) than vice-versa. In every way, he gets a boost - what does Constantinople get from this alliance that justifies doing that?

PS, regarding the overall logistical concerns of a combined Empire, may we remember that, aside from trans-rhenish Germany, all this territory was, for several centuries, ruled by one government (the same government we're proposing rule the thing in this scenario).

The problem is that said empire didn't have to send forces from Asia Minor to deal with pests in Gaul (or vice-versa).

By contrast, this one is being asked to do so. After three plus centuries of indifference to the Roman roads and a general slackening of administration in the West.

If everyone was a-okay with it, that would be one thing, but we're not looking at that in addressing Constantinple riding herd on the unruly Frankish subkings.

So we may remember it, but we should also note that it has issues that were less of a situation then.

 

[Mipp]

Other possibilities:

The son (Charles Constantine?) of Louis the Blind and Anna, daughter of Byzantine emperor Leo VI, somehow ends up succeeding both his father as HRE and cousin Romanos II as ERE.

Otto III lives longer and somehow unites both empires (his mother was a niece-by-marriage of Ioannes I Tzimiskes).