Now it is possible that I read something about Christians being 40% of the Mesopotamian population and have misremembered that as being the figure for the whole empire.
And yes you are likely right that it was the late Sassanian efforts to homogenize Zoroastrianism that was most responsible for the particular form of modern Zoroastrianism. But we can't be sure about that. There are a number of features of the Islamic conquests which help to obscure some of the details of the Sassanian period, most importantly the informational bottleneck. Zoroastrianism went from the likely dominant faith of greater Persia to the faith of a small group of people living in and around Bombay and some scattered villages in Iran itself. Most of the actual literature we have is from that small community in India.
40% of Mesopotamian population is a lot more reasonable, though I personally still think it's probably a bit too large, but I was unable to find an estimate of how many Christians lived in the empire. On the Zoroastrian part, however, I should note again that the majority of Zoroastrian sources were compiled and codified in the Islamic period, we know that the Sasanians made a huge deal out of their efforts to compile the Avesta and similar things as well as to make an end to the much cooler oral practice of "mumbling" the Avesta (oral recitation basically), which we can think of in the context of Sasanian hostility towards Mazdak's reform movement and the Manichaeans whom the later Sasanians specifically viewed as
zandik (heretics) and subjected to heavy persecution. I think the picture formed by this makes it all very clear that the Sasanians - whom I should note made the orthodox upper mobadate the core of their power - were
the major force for the creation of orthodoxy and the eradication of the previous
cashtag system.
We can see many traces just in the existence of various important Zoroastrian texts. The
Denkard refers to Khosrau I as
im Bay (his present Majesty) in Middle Persian, making it clear that it was copied from a Sasanian-period text written in Khosrau I's reign. The fact that the majority of Zoroastrian texts from the Islamic period are completely silent on matters such as pilgrimage (
evarz) suggests that rather than being
written in this period, they were compiled from high-status Sasanian religious manuscripts, which - in traditional royal style - kept their distance from aspects of popular religion, again emphasizing a Sasanian origin. Shaked and Boyce argued (Shaked, 1984; Boyce, 1968a) that the majority of Islamic-period Zoroastrian sources go back to Sasanian-period ones, which were later translated into Arabic and that the
Tansarnameh represents an authentic Sasanian core. As can be seen as early as Shapur I's reign, Kartir punished
zandik in newly conquered regions
and in the Iranian lands for the sin of not "heeding the proper explanation", very clearly showing that even in the early or middle Sasanian period, an understanding of
wizar (sometimes translated as canon, but "explanation" of the Avesta is better) as promulgated by royal authority and priesthood was present.
As to the matter of the Parsi, I would like to note that I am a Zoroastrian myself and I am indeed familiar with the importance of the Parsi, however it is simply not true to say that the majority of the actual literature we have is from Parsi sources. While it
is true that there are indeed many sources we have from the Parsi, there are still Zoroastrians in Iran, from which we have the Greater Bundahishn, the original Khorde Avesta and many more. The Parsis have preserved many texts for us, yatha ahu vairyo, but they are not the only source and indeed there is a long pattern of Parsis going to Iran whenever a question of orthodoxy appears at home, because Iran was always imagined as the "homeland of orthodoxy". That is the origin of the Rivayats, which originated as questions sent from Parsi mobads to Iranian mobads to ask questions about their procedures, beliefs and practices which would then be sent back with answers. Both communities remained in contact with each other.
I recall listening to some history podcast, basically the sum of it was that in Mesopotamia the Sassanids actively cultivated having Christians opposed to Roman doctrine (Nestorians etc), Jews (to the point of having an official Exilarch) and so on and so forth. This is additionally suported by the fact that until about the 9th-10th centuries, upper Mesopotamia was majority Christian. Iraq was essentially Sassanian Egypt in terms of importance, as it grew most of the food, so the Sassanids liked playing the "we're more tolerant than those romans so don't support them if they come around" card.
Yeah kinda, upper Mesopotamia was definitely majority Christian, but the policy towards Christianity varied a lot. The early Sasanians were a lot more tolerant about Christians than later ones, and openly supported the efforts of the "Persian" eastern Church, but later Sasanians seem to have grown a bit coler on it and produced a number of pretty brutal pogroms. The most bizarre seems to be the Khosrau I-II period, who built their power on the support of the orthodox upper mobadate but seem to have been fairly tolerant towards Christianity, instead choosing to focus on the internal diversity within Zoroastrianism to stamp out. Khosrau II was also notably accepting towards Jews - though as a war-time measure - to the point of giving control of Jerusalem to a committee of Jews and promising the restoration of the Temple, which seemed to have been his policy until the Romans took it back and of course punished the Jews for their temerity to be angry they weren't allowed to enter their own sacred city.
Oh yea, totally agreed. Heraklios probably saw them as just another proxy to fight Rome's wars against the Sassanians; a proxy of the same religion and not occupying that naturally powerful geographic position that the Sassanians held so the two could be on better speaking terms than Rome and Persia
As for the Sabians being better identified, it always warms my heart to see history, whether good or bad, be unearthed and uncovered. History is the story of the human race and every letter, syllable, word, work, picture, song, idea, etc, is an essential part to understanding it all.
The poem is also really lovely, even accounting for the fact it obviously doesn't work as well in English as it does in whatever language he wrote it in (I assume Arabic but Farsi could be). I like the theme of how every group sees something different regarding the divine in the same thing
The original poem was written in Arabic, yeah. I have a few papers on the Sabians I can throw your way in case you're interested.