WI/PC: Byzantine Empire/Sassanids Empire crush eachother

The wars between these two all ended in some sort of stalemate, without a clear victor and always leaving the other side mostly unconquered. Can one side completely conquer the other? IE can the Persians conquer Constantinople, or the Romans Persia? Which side is more likely to win? In the long run, will complete conquest benefit the conqueror or would it just make it harder for them to rule such a vast empire, ie would it exhaust the conqueror's resources? And when Islam rises, will it be harder or easier for the Caliphs to face a large but possibly-overstretched empire?
 
Can one side completely conquer the other? IE can the Persians conquer Constantinople, or the Romans Persia? Which side is more likely to win?
I agree that it is unlikely. But it is possible.
Why not?
Who can win? I don't know... It could be both ways. If one side is lucky to have a prominent great leader like Cyrus the Great or Alexander the Great. But the Romans seem to be a little bit stronger in my humble opinion.
And such an empire might live a hundred years or so. Maybe two hundred.

In the long run, will complete conquest benefit the conqueror or would it just make it harder for them to rule such a vast empire, ie would it exhaust the conqueror's resources? And when Islam rises, will it be harder or easier for the Caliphs to face a large but possibly-overstretched empire?
In the long run such an empire is not too viable, vital.
When Islam rises it won't make much difference if it faces two rival empires or a single overstretched one. The Arabs will win like in OTL.
 
Well it depends what shape the empire is in as far as Islam's arrival to the scene goes. In OTL the Arabs faced two completely exhausted empires who just got done fighting a very long and draining war. Had they face a much stronger Byzantine Empire and or Sassanid Empire, I highly doubt they would have anywhere near as much success as they did in OTL.
 
One way to do it is to have Attila the Hun be the on to invade Constantinople and the Sassanids pick up the asiatic provinces. I think that the Sassanids would definitely need to figure out how to come to terms with Christianity.
 
Pretty sure Islam would be butterflied by this scenario. What we'd likely end up with, long term, is a Christian state based in the Fertile Crescent, with intermittent control over Egypt and Iran. The Iranian highlands would probably break away under their native dynasts, and Anatolia might also be quite difficult to hold, long term.
 
I think t depends on when the conquest happens. If either empire has 50 years or more to recover from conquering the other and assimilate the new peoples and territories then there could be a chance. After all a combined Sassanid ans Byzantine empires would equal to the size of the Achaemenid and Macedonian Empires. While Alexander's empire would be a bad example, the Achaemenid lasted for nearly 200 years, so while difficult, it would be possible.
 

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Complete conquest seems very unlikely, and not really to anyone's benefit. The resulting empire would be nigh-impossible to hold together.
The Byzantines would need help from Europe proper. And it would take a long time to properly pull off. Thats about the only way I see it happening.
 
I think t depends on when the conquest happens. If either empire has 50 years or more to recover from conquering the other and assimilate the new peoples and territories then there could be a chance. After all a combined Sassanid ans Byzantine empires would equal to the size of the Achaemenid and Macedonian Empires. While Alexander's empire would be a bad example, the Achaemenid lasted for nearly 200 years, so while difficult, it would be possible.
That's a lot of peopel and territories to assimulate, very few of which will be happy to accept the rule of the other.
 
There are tons of similarities between the two empires, so perhaps assimilation might not have been out of the question. Its possible that Justinian, rather than pulling Belisarius out of the east after proving himself, he builds up a massive army and has him keep going. He might not be able to absorb everything, but it would be enough to break them
 
There are tons of similarities between the two empires, so perhaps assimilation might not have been out of the question. Its possible that Justinian, rather than pulling Belisarius out of the east after proving himself, he builds up a massive army and has him keep going. He might not be able to absorb everything, but it would be enough to break them

There's zero precedent for "building up a massive army" in our period, though. East Roman armies in the sixth century consisted of between five and twenty thousand men. The figure may have been a bit higher pre-plague, but I think a single army of more than 30,000 men is pretty unlikely to have ever really existed. And 30,000 men ain't gonna be able to swallow Iran whole, especially under such a ruler as Khusro I.

Swallowing Mesopotamia brings a tonne of problems for the Romans too. It's got large Nestorian and Jewish communities who'll resent the Empire. If Chalcedonians and Monophysites could just about be balanced with each other, Nestorians were certainly considered to be beyond the pale, and imperial legislation suggests as such.

And finally, logistics, logistics, logistics. Late Rome, like early Rome, was essentially a state based around the Mediterranean, which means campaigning in Mesopotamia and Iran is always going to be a logistical stretch.
 
And let's say that somehow you manage to raise and train 50,000 men. What do you think the Iranians are going to do?

There's a reason the frontier swayed back and forth in a few areas but neither empire landed a telling blow on the other - neither has the strength to do something the other can't respond to.
 
And let's say that somehow you manage to raise and train 50,000 men. What do you think the Iranians are going to do?

There's a reason the frontier swayed back and forth in a few areas but neither empire landed a telling blow on the other - neither has the strength to do something the other can't respond to.

Essentially this. Both sides would match the other. Whatever the Romans do, the Sassanids would counter, and vice versa.
 
Would it be possible to just have some of Khosrau II's conquests stick? Holding onto the Levant for an extended period of time shouldn't be too much of a strain on Sassanids logistics providing for the Romans not having the wherewithal to oust them before they can be established. Perhaps over a long enough time frame the Sassanids might be able to pick off parts of the Roman Empire to the point that the Romans no longer have the resource base to actually challenge the Sassanids in any serious manner, at least for a period of time. Short of that I can't imagine any real way for the one to defeat the other outright with the result being actual conquest.

The best case for the Romans would probably similar to how the final Roman-Sassanid war ended but at a much lower cost, with the Sassanids falling apart into feudalism and destroying their ability to wage offensive war against Roman power in Mesopotamia. Neither of these really seem like sustainable solutions though, the logistics just favor the entity with the home ground advantage too much for an actual conquest to occur.
 
Would it be possible to just have some of Khosrau II's conquests stick? Holding onto the Levant for an extended period of time shouldn't be too much of a strain on Sassanids logistics providing for the Romans not having the wherewithal to oust them before they can be established. Perhaps over a long enough time frame the Sassanids might be able to pick off parts of the Roman Empire to the point that the Romans no longer have the resource base to actually challenge the Sassanids in any serious manner, at least for a period of time. Short of that I can't imagine any real way for the one to defeat the other outright with the result being actual conquest.

Khosaru's conquests in and of themselves are exhausting, though. That's not a position from which conquests in the Levant are going to stick.
 
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