Quote: 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? The answer: Text. Many items in museums have no specific date but Circa X. I have spent a lot of time in the early 2000s to enable "Sort by date" in museum registrars software I was maintaining despite having it textual
That was my immediate thought too and led to me wondering: How do you represent BCE dates in ISO 8601?
Apparently ISO 8601 always supports YYYY from 0000 (1 BCE) to 9999 (9999 CE). ISO 8601 can also extend beyond those limits if agreed upon by sender and receiver: e.g. -0001 (2 BCE), -0002 (3 BCE), etc.