Manetho and the Ages of Man

I just noticed something interesting about Hesiod's ages of man.

So, Hesiod tells us mankind is descended from the gods, and there was a descent through five ages:

• In the Golden Age, Kronos was king and men lived joyous, carefree lives.
• In the Silver Age, Zeus took over and men lived foolishly, wronging each other and the gods.
• In the Bronze Age, men were violent and warred constantly.
• In the Heroic Age, men were noble and righteous.
• In the Iron Age, men lived short, painful lives of unending toil.

It is well-known that these relate to the astrological ages of Leo, Cancer, Gemini, Taurus, and Aries.

Well, Manetho in his History of Egypt tells us that the gods ruled Egypt before mortals did. (Diodorus Siculus puts a date to this, saying it mortals began to reign around 5000 BC, which was in the age of Taurus.) The gods who ruled Egypt were, in order: Hephaistos (Ptah), Helios (Ra), Sosis/Agathodaemon (Shu), Kronos (Geb), Osiris, Typhon (Seth), and Horos.

There's a nice connection, there. If we assume the gods refer to astrological ages, then righteous Horos was king during the similarly-righteous age of Taurus before handing off kingship to the pharaohs; before him, violent Seth was king during the similarly-violent age of Gemini; before him, benevolent Osiris (e.g. Zeus) was king during the age of Cancer (remember how Plutarch says the people were as beasts and Osiris taught them how to live civilized lives and honor the gods?); and before him, Geb (e.g. Kronos) was king during the age of Leo. It smells like Hesiod got his ages of man from Egypt—certainly, he got a lot of his other myths from there! (By the by, nobody knows the etymology of the Greek word ἥρως ("hero"). It certainly sounds a lot like heru ("Horos")... is the Heroic Age literally named after its king?)

Plato says that, according to the Egyptians, the fall of Atlantis was around 9000 years before his time, which corresponds to the end of the last glacial period and to the age of Leo. I would not be a bit surprised if the "golden age" is an echo of a memory of that once-great civilization; after it fell, a dark age ensued, after which the gods slowly reintroduced civilization to men... plausibly, in Egypt. (Certainly, Plato and Diodorus say that the Egyptians thought so.)

If that's so, then it suggests that the myth of Osiris could be a good deal older than the fifth dynasty (e.g. the Pyramid Texts, which are our first references to it). One wonders how much. Even predating the age of Aries would be an impressive accomplishment, but I've seen references (which I have not yet managed to track down) to myths very similar to Osiris's being found among South American cultures, on the other side of the Atlantic. Does it go back to Atlantis, itself?