One of the little know points of history was prior to the Islamic expansion out of Arabia. Two devastating things happened to the Roman & Persian worlds. First they had just concluded a long bitter, exhausting manpower & treasury’s a very damaging war between the two empires. Second the Roman (Eastern Roman or Byzantine) Empire and the Sassanian Persian Empire suffered one of the first recorded (at least by the West) devastating out breaks of the Black Death (either Bubonic or Pneumatic or both!). Its difficult to tell how Arabia was affected by the out break since little written record has survived and maybe it was unaffected because it was a little bit of the beaten path of trade. Arabic Islam essentially expanded into an exhausted Persian empire. There are a few Eastern Roman records talking about problems with a few non-Christian but Ishmaelite Arab (Interesting term!) tribes and how there were too few troops in the area to oppose them.
That’s interesting, thanks.
Had Alexander & later the Arab & Monghol invaders of Iran not burned down libraries & all sorts of books in Iran, we would most probably now know far more about historical events from the Persian perspective, instead of mostly the Greek historian such as Herodotus. IOW, we now would have a much more balanced account of events.
The moslem-arabs in particular, burned many books, not limited to Philosophy or Zoroastrian religion, but also about Mathematics, Algebra, Geometry, Sciences, Medicine, etc.. - many were written during the Sassanian period; others were much older.
For example, Pythogarus the Greek philosopher and mathematician spent 20 years of his life in Iran and “Babylon”, (which was a part of the ancient Persian Empire), according to his biography. During this time he learned the knowledge of the “Moghaan” (Magi). His philosophy of light was under the influence of Persians who believed in spherical Earth rotating around the central Sun. There has also been doubts about the famous theory of right angle triangles.
Equally, the Greeks had no progressive calculation and mathematics and nothing to offer in Algebra, Babylonians (part of ancient Persian Empire) were using a numeric system and had even invented 0. At this time Greeks used alphabets for numbers.
Btw, if interested in post-Islam period, A book entitled Two Centuries of Silence by Abdolhossein Zarrinkoob (a contemporary Iranian writer/historian) is a good one. It has chapters about pre-Islam history too, but focuses on post-Islam, during & immediately after Arab-Moslem invasion of Persia.