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inclusion: always
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# Temporal Dating Conventions for Ancient History

## BCE Tag Syntax

Factbase supports BCE dates in temporal tags. Always use them — never leave BCE dates untagged.

Supported formats:
- `@t[=331 BCE]` — exact event (Battle of Gaugamela)
- `@t[~280 BCE]` — approximate/state (Pharos Lighthouse built)
- `@t[305 BCE..30 BCE]` — date range (Ptolemaic Egypt)
- `@t[..612 BCE]` — ended at date (fall of Nineveh)
- `@t[911 BCE..]` — started, ongoing from that point

Use `~` prefix for approximate dates common in ancient history. Most pre-classical dates are approximate.

## Dates as Source Validation

In ancient history, dates ARE the scholarship. A date like "~2334 BCE" for Sargon of Akkad encodes decades of archaeological and textual debate. Temporal tags serve double duty:

1. **Factbase temporal tracking** — enabling `as_of` and `during` queries
2. **Source accountability** — every tagged date must have a footnote citing who established that chronology

When answering temporal review questions, always:
- Add the `@t[...]` tag with BCE syntax
- Confirm the source footnote covers the dating (not just the event)
- Note if the date is contested (e.g., Egyptian chronology has high/middle/low variants)

## Ranges vs Exact Dates

- Reigns, periods, dynasties → use ranges: `@t[336 BCE..323 BCE]`
- Battles, founding events → use exact: `@t[=331 BCE]`
- Approximate dates → use tilde: `@t[~2560 BCE]`
- Unknown dates → use `@t[?]` and note why in the review answer