So, in OTL Sassanid (Sasanian) Persia was destroyed when it was absorbed into the Abbasid Caliphate. Flash forward many years and we have the Ottoman Empire in control of the region (plus Anatolia).
So we know how the Ottomans did when it came to their empire. They defeated the Eastern Romans and ruled for quite a few centuries, expanding Islamic influence throughout the Mediterranean. However, what if Islam never existed, preventing OTL's collapse of Sassanid Persia? If the Persians became strong enough to conquer the Eastern Roman Empire in a similar fashion to how the Ottomans did it, how would their empire have fared? Would they have been successful in spreading Zoroastrian influence? How would their relations with the west be? Would the pope/the rest of western Europe see Zoroastrians the way OTL's pope/western Europe see Muslims? Would there have been crusades led against the Persians? Discuss below!
So we know how the Ottomans did when it came to their empire. They defeated the Eastern Romans and ruled for quite a few centuries, expanding Islamic influence throughout the Mediterranean. However, what if Islam never existed, preventing OTL's collapse of Sassanid Persia? If the Persians became strong enough to conquer the Eastern Roman Empire in a similar fashion to how the Ottomans did it, how would their empire have fared? Would they have been successful in spreading Zoroastrian influence? How would their relations with the west be? Would the pope/the rest of western Europe see Zoroastrians the way OTL's pope/western Europe see Muslims? Would there have been crusades led against the Persians? Discuss below!