[lukeschlather]

Or they had a detailed record of all eclipses going back several hundred years. I guess it would make sense that this was the record but it's also plausible they had some ritual reason to refer to a date of an eclipse when building this thing.

[nraynaud]

a continuous chain of memories is enough to consider it the same culture. They did not imply that the date was the carving date, but that the culture extended as far back as that date.