Existing Wording: date: A date, or partial date (e.g. just year or year + month) as used in human communication. The format is YYYY, YYYY-MM, or YYYY-MM-DD, e.g. 2018, 1973-06, or 1905-08-23.

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Regex: ([0-9]([0-9]([0-9][1-9]|[1-9]0)|[1-9]00)|[1-9]000)((0[1-9]|1[0-2])((0[1-9]|[1-2][0-9]|3[0-1]))?)?

Comment:

How should dates BCE be conveyed (may be used for archaelogical human remains)? Can we provide any guidance/warning on the cutover to, and dates before, the Julian calendar?

Is the date type only good for post-1700 dates?

Summary:

Clarify how ancient dates are expressed