Could you make a thread in Chat explaining this? As someone who was raised a Christian, I am absolutely befuddled as to what you mean by this. However, I do not want this thread to be derailed.
WI: Khosrau II captures/executes/assassinates Mohammed
- Thread starter Harald Sigurdson II
- Start date
Could you make a thread in Chat explaining this? As someone who was raised a Christian, I am absolutely befuddled as to what you mean by this. However, I do not want this thread to be derailed.
GdwnsnHo
Banned
It is interesting when talking of migrations by the Arabs - as both sides have EXTENSIVE experience in dealing with violent migrations.
Most important to this would be the Ghassanids (serving Rome) and any Lakmanid remnants (rivals, former Sassanid client state that raided Persia like a boss).
The Lakmanids had a ruler who wanted a united Arabia, but he died centuries before this, after raiding Persia, who in turn squished them, made them a client state - and then a few centuries later destroyed their capital to rebuild another city, turning many Lakmanids into spies for the Arabs.
The Ghassanids give us an interesting example as we don't know if there was any early violence as their first appearance in records was the development of a client state.
Based on these examples - Persia would likely not have peaceful relations with invading Arabs - whilst Rome has a potential chance to, depending on the reactions of the Ghassanids.
Personally I don't see anything too unlikely in Rome offering to assist the arabs in claiming new territory in Mespotamia in exchange for becoming a client state. In addition, they could use the Arabs to bulk out their armies and repopulate any territories that needed men (but could still Romanise the Arabs) and even use them to turn Arabia into a series of client states, and enforce their rule on the other former foederati in the west. At the very least we'd see the benefits of a substantial population influx (with potential for not losing a huge chunk of the empire!) YIPPIE!
Persia has just wiped out a client state, and captured/killed Mohammed - his followers may very well attempt to wreak havoc on Persia for this, if they can, but I can see Persia facing the wrath of the more violent arabians, whether successful or not.
Either way - Persia is gonna be in a worse place than Rome at the end of this.
EDIT : It'd be interesting to see how the captured Mohammeds teachings influence the Ghassanids, Free Arabs, and even various Christian sects - a major factor in all of this could be which faith wins out - 'Islam' and its schisms, Zoroastrianism and its schisms, or Christianity and its Schisms.
Most important to this would be the Ghassanids (serving Rome) and any Lakmanid remnants (rivals, former Sassanid client state that raided Persia like a boss).
The Lakmanids had a ruler who wanted a united Arabia, but he died centuries before this, after raiding Persia, who in turn squished them, made them a client state - and then a few centuries later destroyed their capital to rebuild another city, turning many Lakmanids into spies for the Arabs.
The Ghassanids give us an interesting example as we don't know if there was any early violence as their first appearance in records was the development of a client state.
Based on these examples - Persia would likely not have peaceful relations with invading Arabs - whilst Rome has a potential chance to, depending on the reactions of the Ghassanids.
Personally I don't see anything too unlikely in Rome offering to assist the arabs in claiming new territory in Mespotamia in exchange for becoming a client state. In addition, they could use the Arabs to bulk out their armies and repopulate any territories that needed men (but could still Romanise the Arabs) and even use them to turn Arabia into a series of client states, and enforce their rule on the other former foederati in the west. At the very least we'd see the benefits of a substantial population influx (with potential for not losing a huge chunk of the empire!) YIPPIE!
Persia has just wiped out a client state, and captured/killed Mohammed - his followers may very well attempt to wreak havoc on Persia for this, if they can, but I can see Persia facing the wrath of the more violent arabians, whether successful or not.
Either way - Persia is gonna be in a worse place than Rome at the end of this.
EDIT : It'd be interesting to see how the captured Mohammeds teachings influence the Ghassanids, Free Arabs, and even various Christian sects - a major factor in all of this could be which faith wins out - 'Islam' and its schisms, Zoroastrianism and its schisms, or Christianity and its Schisms.
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Now that's utterly ridiculous.
No matter what your opinion on Joseph Smith or Mormonism in general is, he was indeed the spiritual founder of the Latter Day Saint movement. The circumstances of his life, how this religious movement was actually founded, or what beliefs they hold today is completely irrelevant here; what is relevant however is the fact that he managed to actually build this movement. If we couldn't even mention (!) a particular branch of Christianity anymore just because of its perceived offensiveness to other branches, we could no longer discuss any religious topic either, as there would always be branches that find certain points offensive.
And birdboy2000 made a perfectly fine and objective statement, without any intentional or unintentional affront.
Often? So far as I know it's only happened once...but damn did it work wonders for the faith when it did!
No, see, it's not that he got killed, it's that they couldn't make him stay dead.
Lunarwolf
Banned
Eye of the Beholder, innit?
however in an effort to not derail further, i'm dropping the subject.
Anyway...
I'll quote this, since it may have suffered from bottom-of-the-page syndrome.
I'll quote this, since it may have suffered from bottom-of-the-page syndrome.
First, as other people have said idk if this would change history all too much as the Muslim community still has Abu Bakr, Ali ibn Talib, Umar bin al-Khattab and technical Khalid ibn Walid. However for the sake of argument I will assume events will change and without Muhammad Islam will be changed tremendously, I will also assume Khalid ibn Walid does not convert without Muhammad to receive him at Medina.
If this is to happen then I can see a longer war between Muslims and the Quryash making the Hejaz more fractured. That being said it is likely that the Muslims will be victorious and will unite the Hejaz, however without the swift conquest of the Middle East and Arabia there will be more dissection in Islam, most likely a stronger and more fearsome Kharajite movement which could fracture the Islamic state in the Hejaz.
At the same time I can see the Sassanids attempt to reconstruct themselves after the disastrous wars with the Byzantines(which will be preoccupied with the Avar khaganate). I seriously do not see the Sassanids expand and it is possible they loose Oman to the natives or even rogue Muslims ( Khawarij ) seeking to take land from the Persians. These Khawarij could possibly upon breaking free from the Hejaz launch raids and small scale invasions of Sassanid and Byzantine territory. In time these Khawarij could completely separate from orthodox Islam creating extremely distinct religions who just use the same book and traditions (Quran,Hadiths and Sharia) with the orthodoxy in Hejaz proclaims the caliph must be related to Muhammad while the Khawarij proclaim only the most knowledgable can rule and shout their slogan "no rule but gods". Also the different sects would have different types of followers with orthodoxy catching on around the coast and among the merchants and elite while the Khawarij would primarily be Bedouins who had previously spent their life raiding and from lower clans and tribes.
Back to the Persians, they would most likely continue their rule despite these Khawarij raids and will attempt to play the sects against each other effectively nullifying a full on invasion which at the moment they would not be able to handle.
Byzantines at the same time without the Arab invasion, can resume conqeusts of southern Italy and deal with the Avar Khaganate. Without large piracy by the Arabs the Mediterranean will be somewhat safer and will have more information spread between Europe and Africa . While the Mediterranean would be safer, inland middle east will be more dangerous as the borders of three holstile enemies create no room for trade and the flowing of ideas (how the Islamic golden age began) these hostile borders would be raiding Khawarij and Hejazi (orthodox Muslims in this scenario), the Sassanids and Byzantines with both withholding information and trade from the other.
With that said the Hejazi with their merchant tendencies could possibly create a rich merchant society with friendly ties to Aksum and possibly Byzantine Egypt.
To Aksum, without fear of Islam Aksum retains its trading power in the gulf of Aden and in the Indian Ocean, however I foresee them still having trouble with Somalians which would likely convert to the Hejazi version of Islam, via Arab merchants. In Yemen it is a toss up between Aksum, Hejaz and native tribes ( Qataban) and could probably be split in threes by the states.
In Europe the various kingdoms would be unlikely unite ( no Charlemagne) without the threat of Islam, most likely the Visigoths retain control over Spain, plus without Arab influences the Iberians are likely to adopt Spanish and perhaps continue speaking a Germanic language. The Berbers and Tauregs are slowly Christianised however not at the same speed as with Islam and most likely West Africa will only be loosely influenced by Christianity, as well it is possible the Berbers and Tauregs developed their own forms of Christianity (Arianism), and due to their relative isolation to the Christian power bases they will retain this form of Christianity with little to no persecution. Also in North Africa, African Romance languages will dominate the coast while Punic continues its decline, however with out their easy assimilation to Arabic avoided their communities could last for much longer in isolated enclaves throughout Libya.
In Egypt it is possible for a Coptic revolt (possibly supportorted by Hejaz and Aksum) which if happened soon enough could succeed as Byzantium deals with threats on its northern border, however it is likely they retain rule over Carthage and in the future will attempt reconqeust. In the Levant, Byzantine rule is unopposed except for Khawarij raids and the Sassanid threat. In Anatolia Without the constant raids from the caliphates, prospers and raises above the Levant ( which will be similar to otl's Anatolia.
In China, the Tang are relatively unaffected by the change however with good relations with the Sassanids, might have a stronger power in central Asia similar to the Qing dynasty, however it is unlikely they will expand further due to the incoming An Lushun rebellion (which was independent from Islam). In India the status quo is kept with no Arab attacks on the Indus retain a larger cultural size with more Hindu style regimes and obviously larger Hinduism/Buddhism. In Afganistan the Zabul retain their religion in the worship of Zun and will retain independence until the Turks inevitably ride into their land. Buddhism will also have a large following in northern Afganistan, with large amounts of Manichaens. Sogdiana will retain its identity without Islam and but will soon succumb to invading steppe hordes, they remain Manichaens & Zoroastrians. Overall central Asia remains extremely religiously mixed, between Buddhism, Manichaens and Nestorians. The Turks are up in the air as far as conversion goes and could be similar to the Mongols vastly mixed and territory they conquer will begin to change them. Most likely the Turkish horde will strike Persia and India soon enough, however it is likely after crushing the Sassanids move on to India (richer) without the allure of Islam will be less inclined to invade further west than just raids. This could prove to be the end of the Sassanids as a new dynasty rises in its place. The Byzantines will be less effected by this and could possibly launch its own invasion of Persia (most likely failing).
The Byzantines will also have to face invasions by the Khazars who most likely retain tengrism without Islam who will be more aggressive in this scenario with out the monster Abbasids on its southern border. In fact it is likely all the steppe hordes in the north ( Cumans, Pechengs, Bulgars and Qipchak) are more aggressive without Islam.
As far as languages go Turkish will only be heard east of Iraq and will be confined to India and Afganistan (not counting possible mercenaries used in various realms), Arabic is much less dominant and is found only in Arabia with more dialects then today's Arabian peninsula, in Yemen and Oman South Arabian languages continue to dominate. Maltese most likely doesn't occur and is replaced by a Romance language or Greek (if under Byzantium). Aramaic/Suriac remains dominant throughout Iraq and the Levant and continues as the language of eastern Christianity. Persian keeps the Pahlavi script with no loan words from Arabic and a more info Euopean feel. The Turks are also likely to use the Pajkavi script, no Urdu in India. Nubia will stay within the Cushitic field of Afro-Eurasian languages and obviously not speak Arabic except for maybe the coast, were Hejazi Islam could grow. As far as religion goes Hinduism is by far more widespread most likely dominating Buddhism in Indonesia and Khmer. Buddhism will continue in Afganistan and will be part of the three way dog fight in Central Asia it will also have a larger following in the west without Islam (Persia). Christianity remains United and stronger in its birthplace (levant) and will have a larger following in Africa however without Iskam it is possible Christianity dies not gain the same traction in the north ( Baltic coast, East Germany, Poland, and Scandanavia). Russia is a toss up however it is still likely they are drawn to Byzantium, thus converting to Christianity. Islam outside of the Arabian Peninsula is a toss up and depends on how interested the Hejaz is into trading. Manichaeism, without widespread suppression by Islam will be a world religion being highly influential in Iraq (split by Zoroastrians, Manichaens, Nestorians, Mandaeism, Yazidis and Islam) and will gain larger followings in India and Central Asia. Zoroastrianism remains the cultural religion of Iran and will overtime become basically immune to Abrahamic religions (like Hinduism), Zoroastianism however is still unlikely to prostalyze, becoming almost just like a monotheist Hinduism.
Everything past this idk because there are two many butterfly's. Btw my first post.
If this is to happen then I can see a longer war between Muslims and the Quryash making the Hejaz more fractured. That being said it is likely that the Muslims will be victorious and will unite the Hejaz, however without the swift conquest of the Middle East and Arabia there will be more dissection in Islam, most likely a stronger and more fearsome Kharajite movement which could fracture the Islamic state in the Hejaz.
At the same time I can see the Sassanids attempt to reconstruct themselves after the disastrous wars with the Byzantines(which will be preoccupied with the Avar khaganate). I seriously do not see the Sassanids expand and it is possible they loose Oman to the natives or even rogue Muslims ( Khawarij ) seeking to take land from the Persians. These Khawarij could possibly upon breaking free from the Hejaz launch raids and small scale invasions of Sassanid and Byzantine territory. In time these Khawarij could completely separate from orthodox Islam creating extremely distinct religions who just use the same book and traditions (Quran,Hadiths and Sharia) with the orthodoxy in Hejaz proclaims the caliph must be related to Muhammad while the Khawarij proclaim only the most knowledgable can rule and shout their slogan "no rule but gods". Also the different sects would have different types of followers with orthodoxy catching on around the coast and among the merchants and elite while the Khawarij would primarily be Bedouins who had previously spent their life raiding and from lower clans and tribes.
Back to the Persians, they would most likely continue their rule despite these Khawarij raids and will attempt to play the sects against each other effectively nullifying a full on invasion which at the moment they would not be able to handle.
Byzantines at the same time without the Arab invasion, can resume conqeusts of southern Italy and deal with the Avar Khaganate. Without large piracy by the Arabs the Mediterranean will be somewhat safer and will have more information spread between Europe and Africa . While the Mediterranean would be safer, inland middle east will be more dangerous as the borders of three holstile enemies create no room for trade and the flowing of ideas (how the Islamic golden age began) these hostile borders would be raiding Khawarij and Hejazi (orthodox Muslims in this scenario), the Sassanids and Byzantines with both withholding information and trade from the other.
With that said the Hejazi with their merchant tendencies could possibly create a rich merchant society with friendly ties to Aksum and possibly Byzantine Egypt.
To Aksum, without fear of Islam Aksum retains its trading power in the gulf of Aden and in the Indian Ocean, however I foresee them still having trouble with Somalians which would likely convert to the Hejazi version of Islam, via Arab merchants. In Yemen it is a toss up between Aksum, Hejaz and native tribes ( Qataban) and could probably be split in threes by the states.
In Europe the various kingdoms would be unlikely unite ( no Charlemagne) without the threat of Islam, most likely the Visigoths retain control over Spain, plus without Arab influences the Iberians are likely to adopt Spanish and perhaps continue speaking a Germanic language. The Berbers and Tauregs are slowly Christianised however not at the same speed as with Islam and most likely West Africa will only be loosely influenced by Christianity, as well it is possible the Berbers and Tauregs developed their own forms of Christianity (Arianism), and due to their relative isolation to the Christian power bases they will retain this form of Christianity with little to no persecution. Also in North Africa, African Romance languages will dominate the coast while Punic continues its decline, however with out their easy assimilation to Arabic avoided their communities could last for much longer in isolated enclaves throughout Libya.
In Egypt it is possible for a Coptic revolt (possibly supportorted by Hejaz and Aksum) which if happened soon enough could succeed as Byzantium deals with threats on its northern border, however it is likely they retain rule over Carthage and in the future will attempt reconqeust. In the Levant, Byzantine rule is unopposed except for Khawarij raids and the Sassanid threat. In Anatolia Without the constant raids from the caliphates, prospers and raises above the Levant ( which will be similar to otl's Anatolia.
In China, the Tang are relatively unaffected by the change however with good relations with the Sassanids, might have a stronger power in central Asia similar to the Qing dynasty, however it is unlikely they will expand further due to the incoming An Lushun rebellion (which was independent from Islam). In India the status quo is kept with no Arab attacks on the Indus retain a larger cultural size with more Hindu style regimes and obviously larger Hinduism/Buddhism. In Afganistan the Zabul retain their religion in the worship of Zun and will retain independence until the Turks inevitably ride into their land. Buddhism will also have a large following in northern Afganistan, with large amounts of Manichaens. Sogdiana will retain its identity without Islam and but will soon succumb to invading steppe hordes, they remain Manichaens & Zoroastrians. Overall central Asia remains extremely religiously mixed, between Buddhism, Manichaens and Nestorians. The Turks are up in the air as far as conversion goes and could be similar to the Mongols vastly mixed and territory they conquer will begin to change them. Most likely the Turkish horde will strike Persia and India soon enough, however it is likely after crushing the Sassanids move on to India (richer) without the allure of Islam will be less inclined to invade further west than just raids. This could prove to be the end of the Sassanids as a new dynasty rises in its place. The Byzantines will be less effected by this and could possibly launch its own invasion of Persia (most likely failing).
The Byzantines will also have to face invasions by the Khazars who most likely retain tengrism without Islam who will be more aggressive in this scenario with out the monster Abbasids on its southern border. In fact it is likely all the steppe hordes in the north ( Cumans, Pechengs, Bulgars and Qipchak) are more aggressive without Islam.
As far as languages go Turkish will only be heard east of Iraq and will be confined to India and Afganistan (not counting possible mercenaries used in various realms), Arabic is much less dominant and is found only in Arabia with more dialects then today's Arabian peninsula, in Yemen and Oman South Arabian languages continue to dominate. Maltese most likely doesn't occur and is replaced by a Romance language or Greek (if under Byzantium). Aramaic/Suriac remains dominant throughout Iraq and the Levant and continues as the language of eastern Christianity. Persian keeps the Pahlavi script with no loan words from Arabic and a more info Euopean feel. The Turks are also likely to use the Pajkavi script, no Urdu in India. Nubia will stay within the Cushitic field of Afro-Eurasian languages and obviously not speak Arabic except for maybe the coast, were Hejazi Islam could grow. As far as religion goes Hinduism is by far more widespread most likely dominating Buddhism in Indonesia and Khmer. Buddhism will continue in Afganistan and will be part of the three way dog fight in Central Asia it will also have a larger following in the west without Islam (Persia). Christianity remains United and stronger in its birthplace (levant) and will have a larger following in Africa however without Iskam it is possible Christianity dies not gain the same traction in the north ( Baltic coast, East Germany, Poland, and Scandanavia). Russia is a toss up however it is still likely they are drawn to Byzantium, thus converting to Christianity. Islam outside of the Arabian Peninsula is a toss up and depends on how interested the Hejaz is into trading. Manichaeism, without widespread suppression by Islam will be a world religion being highly influential in Iraq (split by Zoroastrians, Manichaens, Nestorians, Mandaeism, Yazidis and Islam) and will gain larger followings in India and Central Asia. Zoroastrianism remains the cultural religion of Iran and will overtime become basically immune to Abrahamic religions (like Hinduism), Zoroastianism however is still unlikely to prostalyze, becoming almost just like a monotheist Hinduism.
Everything past this idk because there are two many butterfly's. Btw my first post.
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A bit of optimism on my part. Especially regarding the Tapurianis who along with the Caspian Sea peoples I have a favoritism for.
For the Byzantines though by this point the Slavs had already overrun the Balkans which was a major weak point for the Greeks. Blunted by the Iranian Powers That Be in the Middle East the Byzantines may very well sap their strength fighting in the West. Though the Sassanids are definitely done for, unless Yaz. Manages to become a greater leader and take charge from his puppeteers and lead a campaign to take back the splintered eastern Iranian plateau.
I won't be qualified to critique your spelling, one way or other, until the paragraph breaks get in and I don't have to climb a wall of text.
Welcome to the forum, John! Excellent post, thanks for adding line breaks.
A note on Aksum. Ethiopia is somewhat better off in this timeline simply because the maintenance of the Rome/Persia militarized border means the Red Sea trade route continues to be the major east/west trade artery. Islam's OTL rise moved that trade to the Persian Gulf. However, Aksum itself was on its last legs even before this POD. The plague of Justinian, which originated near Aksum, is thought to have been most virulent in sub-Saharan Africa and to have seriously devastated the Aksumite state. Additionally, by the 6th century, the agricultural land surrounding Aksum was heavily overfarmed, leading to the abandonment of that city as a political and commercial center by ~650. So while East Africa likely does better here, the state of Aksum is not necessarily the beneficiary.
One idle, if somewhat related thought. I wonder if a breakaway Coptic state centered on Egypt might engage in any southward expansion? After all, a number of the most valuable African trade products (Ivory, Gold, exotic animals) could be found in abundance along the Nile south of the Sahara. Egypt seems naturally positioned to succeed Aksum as the hegemonic power in the Red Sea, so it follows they would have a vested interest in controlling the key ports on both sides of Sea (I'm thinking specifically about Adulis and the Yemeni coast line). The land between Adulis and Egypt proper is the domain of the Beja, nomadic tribes who regularly made a nuisance of themselves to both Aksum and Egypt throughout history and who the Coptic Egyptian state would have an interest in controlling. And finally, because of the legacy of Aksum, much of Ethiopia and the Nubian Nile Kingdoms are at this point Coptic Christian, meaning there is a cultural continuity between the civilizations, which would help the Egyptians extend hegemony over the region.
Thanks for the info on Aksum. So if a independent Coptic Egypt rises, as well as an Ethiopian state how would the two react to each other?
Also I figure that the Coptic Egypt would have to compete with the Islamic caliphate in The Hejaz.If that is the case, there could be frequent piracy and naval engagements in the Red Sea. Which Byzantium might try to capitalize on.
Also I wonder how a Egyptian dominated East Africa would look as far as languages. Would Coptic be able to become the common language of East Africa(at least in urban coastal areas) and how would this effect Arabic right across the Red Sea?
I feel like that is very possible, by using Zoroastrianism to legitimize each dynasties rule. Theoretically every ruler would be the relative of Ahura Mazda, this is very similar to the the son of heaven in China. However this system depends on Zoroastrianism (due to Zoroastrianism's glorification of Persian society and culture). It would be interesting if Persia developes a concept of the Middle Kingdom in reference to Persia similar to China.
I think that's sort of what happens in some post-Islamic Persian and Zoroastrian literature. I also think that Zoroastrianism wouldn't stay the majority religion though; it would probably wind up occupying somewhat of the same position as the imperial cult in China did. Maybe Christianity, Zoroastrianism, and alt-Islam would have a relationship similar to Buddhism, Taoism, and Confucianism did(c.f. the "vinegar tasters").
That would be interesting, figured that it could turn that way. But I also think it could be possible that Ziroastrianism continues to strengthens its ties to the Persian people, similar to how Hinduism remained the religion of the people of the Indian subcontinent. However if Iraq continues to remain the more populated part of the Sassanids (or which ever dynasty rules) it is likely that Zoroastrianism isn't the largest religion. That being said for a religion to take over it would have to rule Iraq. Which would be between Nestorianism vs Manichaeism.
I've read it now, and you have very little to apologize for on the spelling front. Most of it can be treated as transcription to Roman letters anyway.
Another voice added to the chorus pointing that out, and I have to join it. About something this big, this far back? Any speculation falls under Will Shetterly's dictum that there are no "correct" alternate histories, only plausible ones.
I wish I could recall a reliable source, but I thought I remembered reading that by the time of the Sassanid Dynasty, Zoroastrianism no longer had a mass following. The Sassanids helped to revive it somewhat through state sponsorship (including rebuilding decrepit shrines?) but that only resuscitated the religion so much. By this time, Nestorian Christianity, Manichaeism, Buddhism, and other religious groups were all vying for followers in a religiously plural society.
If that is true, I think the China comparison is likely to be more apt. But that requires more research then I have time for right now. Maybe you're more knowledgeable on the period then me?
Zoroastrianism was, during the Sassanid Empire, still by and large the main religion in Persia. Nestorian Christianity was popular in the west of the Empire (Asoristan/Babylonia) whilst Buddhism was popular in Kabolistan, but elsewhere (Sakastan, Pars, Sogdia, etc) were still very much so Zoroastrian.
Zoroastrianism was still the main religion in the area equivalent to modern Iran, Turkmenistan (Merv), Azerbaijan and Herat (West Afghanistan) until the Abbasids, and even then Zoroastrianism remained dominant in Yazd, Kerman, Shirvan-Aturapakan and Taburistan, only ending in Shirvan-Aturapakan with the arrival of Oghuz Turks under the Seljuks and Taburistan around the 14th century. It is still a large minority in Yazd and Kerman today.
The letters from Muhammad to Khusro II are probably forged later on and were never really sent - the Shahanshah was is such a high position of authority that even letters from other respected kings would struggle to reach his court directly.
For this reason, it is unlikely that Khusro II (who died in 628) had any idea about who Muhammad was, but if we assume he somehow finds out (this requires an earlier POD), he will probably view it as no more of a threat, in fact probably much less, than of the Gokturks or Hephthalites. But if for whatever reason he does view the Arabs as a big enough threat, he would probably first send his Himyarite (Yemeni Jewish) dependency against Muhammad. Most likely the Himyarites would greatly underestimate Muhammad's strength, send a large skirmish force or at best a small army against him and lose, which would probably convince the Yemeni people that Muhammad is a prophet of God (this is what happened in reality when the Caliphate took control of Yemen).
If by the blessings of Ormazd we assume Muhammad is captured, it is unlikely he is exiled or spared. Khusro II was very fond of execution when it came to rivals. What happens next isn't easy to say - it depends on how early he is captured and killed. Let's not forget that the Islamic forces under Muhammad did not capture Mecca until 2 years after Khusro II's death. He doesn't really have a lot of notoriety. If he is captured in 627/28? Well this could be interesting. It could really, really rile the Muslims up or it could ruin them. The latter is more likely - the capture of Mecca is the real turning point.
TL;DR I think that in the HIGHLY unlikely event that Khusro II bothers to send anyone to capture Muhammad and then actually captures Muhammad, he will be executed and this will most likely result in the breaking up of the Muslim forces in disbelief and shock since it is 2 years minimum before the capture of Mecca.
Zoroastrianism was still the main religion in the area equivalent to modern Iran, Turkmenistan (Merv), Azerbaijan and Herat (West Afghanistan) until the Abbasids, and even then Zoroastrianism remained dominant in Yazd, Kerman, Shirvan-Aturapakan and Taburistan, only ending in Shirvan-Aturapakan with the arrival of Oghuz Turks under the Seljuks and Taburistan around the 14th century. It is still a large minority in Yazd and Kerman today.
The letters from Muhammad to Khusro II are probably forged later on and were never really sent - the Shahanshah was is such a high position of authority that even letters from other respected kings would struggle to reach his court directly.
For this reason, it is unlikely that Khusro II (who died in 628) had any idea about who Muhammad was, but if we assume he somehow finds out (this requires an earlier POD), he will probably view it as no more of a threat, in fact probably much less, than of the Gokturks or Hephthalites. But if for whatever reason he does view the Arabs as a big enough threat, he would probably first send his Himyarite (Yemeni Jewish) dependency against Muhammad. Most likely the Himyarites would greatly underestimate Muhammad's strength, send a large skirmish force or at best a small army against him and lose, which would probably convince the Yemeni people that Muhammad is a prophet of God (this is what happened in reality when the Caliphate took control of Yemen).
If by the blessings of Ormazd we assume Muhammad is captured, it is unlikely he is exiled or spared. Khusro II was very fond of execution when it came to rivals. What happens next isn't easy to say - it depends on how early he is captured and killed. Let's not forget that the Islamic forces under Muhammad did not capture Mecca until 2 years after Khusro II's death. He doesn't really have a lot of notoriety. If he is captured in 627/28? Well this could be interesting. It could really, really rile the Muslims up or it could ruin them. The latter is more likely - the capture of Mecca is the real turning point.
TL;DR I think that in the HIGHLY unlikely event that Khusro II bothers to send anyone to capture Muhammad and then actually captures Muhammad, he will be executed and this will most likely result in the breaking up of the Muslim forces in disbelief and shock since it is 2 years minimum before the capture of Mecca.
I'd agree with this: the same goes for the supposed letters to Heraclius.
As for Byzantium in this scenario, I'll make the point that I always make, and is always ignored: namely that a "Coptic revolt" is extremely unlikely to happen. There wasn't a distinct Egyptian identity to forge such a revolt in the seventh century. All of the educated classes who could have led a rebellion were thoroughly culturally Greek (which of course in the East is synonymous with Roman) and part of a world that clearly looked towards Constantinople and the Mediterranean, rather than inwards to Egypt. Furthermore, the total absence of religious revolt against Constantinople by anti-Chalcedonian provincials in either period of Roman/Byzantine rule over them (fifth to seventh centuries and tenth to eleventh centuries) is I think suggestive.
About the only chance I can see for a breakaway Egyptian state is one happening almost "accidentally", with a rebellious general somehow taking Egypt but being unable to advance further from there, and Constantinople being unable to deal with the pretender. The Egyptian army itself was pretty marginal compared to the major forces stationed on the Danube and Euphrates, so I think such a rebellion would have to initially begin outside Egypt, but end up being contained to there.
In a scenario where the Arab (I deliberately don't say "Islamic", because I think it's dubious as to whether the first generation conquerors were actually Muslims as we understand the term) conquests are aborted early, the slow reconstruction of Constantinopolitan rule over the Eastern provinces continues. An early priority will be to put together some sort of doctrinal fudge that accommodates non-Chalcedonian opinion, and, assuming no further military disasters, there's no reason this shouldn't stick. Monothelitism IOTL after all was abandoned after continued Arab successes in the 670s made it abundantly clear in Constantinople that God's favour had not returned to the Empire: the same goes for Iconoclasm in the 830s. Unlike Iconoclasm, a Chalcedonian fudge doctrine is unlikely to incur significant popular disapproval, simply because most people won't understand it: so I think it has a significantly greater chance of sticking.
In military terms, it all depends on how quickly Iran is put back together. Assuming a relative respite in the East that lasts for, say, a generation or so, I'd imagine military efforts will be directed towards the Balkans, where there are plenty of easy victories to buoy an imperial government that depends on an image of the God-blessed, victorious Roman Emperor. All being well, I think the priority would perhaps be to first secure the Danube, before dealing with the Sclavenes within imperial territory. As with OTL, population transfers of defeated Sclavenes to Anatolia are quite likely. I can also see some Sclavenic warlords being allowed to remain within the Empire in exchange for conversion to Christianity, and a fairly "fuzzy" provincial system developing in the area, similar to that which existed in Syria in the sixth century with nomadic Arabs and Roman provincials.
If, on the other hand, Iran bounces back quickly, then there can be no reasonable doubt that all efforts will go to defending Roman interests in the Caucasus and northern Mesopotamia. The Balkans and Italy will continue to be largely ignored and starved of resources: perhaps not by quite so much as OTL, but both theatres will certainly be very much a side show. Constantinople's priorities can be summarised as:
1. Eastern enemies
2. Balkan enemies
3. Italian enemies
4. All other enemies
And this is pretty consistent throughout the Empire's history, certainly until the Komnenids, with only occasional aberrations: under Justinian, for example, you can arguably swap 2 and 3 around, although even Justinian spent a lot of money trying to fortify centres in the Balkans and not a great deal of money trying to reconquer the West.
Hope that this is helpful!