> I wonder how people store dates older than this. Maybe if I’m a British Museum manager, and I want to keep theft inventory details. How do I do it? As an epoch? Store it as text? Use some custom system? How do I get it to support all the custom operations that a typical TIMESTAMP supports?

Think about how the museum physical text book store it, as simple text with processing offloaded to the reader (ie: circa 4000BC, Before 2000BC, After ...)

I wonder, if for some problems, we'll move to LLM computation instead of a developer coded solution.

Your variables will be

    let date_1 = "2000 BC"
    let date_2 = "3000 B.C."

    if date_1 > date_2 { .. do something .. }

Fortunately the Met's data is public, both via API and a 330MB CSV. https://github.com/metmuseum/openaccess

Essentially they have an "Object Date" field that's a human-readable string and could be anything, and then they include "Object Start Date" and "Object End Date" that are integer years so that it's machine readable and you can do those comparisons.