They were. The Mayans were perhaps the most consistent and precise, of all people doing astronomy, at least before telescopes. Unlike with almost all other an

They were. The Mayans were perhaps the most consistent and precise, of all people doing astronomy, at least before telescopes. Unlike with almost all other ancient calendars, the alignment of the Mayan calendar to our own is known quite exactly. Scholars have compiled lists with all the eclipses, astronomical records, etc. known from the Mesoamerican writings. There's only one correlation that makes sense, and it aligns with basically everything. Lunar phase, planetary locations, recent eclipses, even the records carved in wood which can be radiocarbon dated (carved on wood that died within the years expected for what's written on it). We can, of course, never really be certain, but it's likely correct that Pakal the Great died on 9.12.11.5.18 -- in August 683, probably on the 29th. With Ancient Egypt, the window of uncertainty with dates in the Middle Kingdom, is about 20 years, and closer to 100 with the Old Kingdom. Nor do we know precisely when Nineveh fell, and that event is recorded in the records of multiple cultures.