The dates are from the same text. And actually from one of the websites quoted above, but a different article (mainly: https://www.astrologicon.org/dorotheus/dorotheus-intro.html
) and this article did not compare these dates with C.E. dates (like the one cited above).
I thought it must a genuine custom (otherwise why the use of abbreviations).
The text is by a modern scholar of Hellenistic mathematics, if I'm not mistaken, and appears to use Ancient Greek spelling style at least, though it is obviously typed in contemporary modern years. By the way is this a more-or-less clean "Ancient Greek" or something more "contaminated" like the notorious 19th century so-called Ancient Greek?
I suspected something like "after Olympics" but Google won't give me any examples. Are there some good places to look for Ancient Greek abbreviations next time?
In this text:
* I know the "correct" modern dates should be around the late 1st century CE for the main discussed original source text ("Ὁ Δωρόθεος ἔζησε τὸν 9ον αἰ. μ.Ὀ.")
* "Φιρμίκος Ματέρνος (12ος αἰ. μ.Ὀ.)" is Firmicus Maternus of middle of the 4th century CE
* earlier "Μανέθων (τέλη 9ου αἰ.)" is Manetho of around 120 CE; "Ἀνουβίων (10ος αἰ.)" is Anubio assessed for 1st century CE without certainty; " Ἡφαιστίων ὁ Θηβαῖος (ἀρχαί 13ου αἰ. μ.Ὀ.)" is Hephaistio of Thebes (early 5th century CE). But all these dates can be speculatory (no direct datings of their work), and different sources can vary on that.
* and onwards for Pahlavi/Arabic translations (say up to 8th-12th century CE, depending on the scholars, for example Pingree says only briefly "We know in fact that Dorotheus was named as king of Egypt in a Pahlavi work made from a translation of the Pahlavi book of Zoroaster dating from about 750" (CE implied) and "It is commonly known that Arabs at the end of the 8th century used the work of Dorotheus")
* "Μιχαήλ Ἰταλικοῦ (20ος αἰ. μ.Ὀ.)" is Μιχαήλ Ἰταλικός; fl. 1136–66
* and "Πάλχος (22ος αἰ. μ.Ὀ.)" is Palchus that was "active in 479 AD" according to one source
How does that answer the question of how this counts the years from the supposedly Olympics?
Thanks so much for many resposes!