# Fictitious Calendar - How to create one?

**URL:** <https://gramps.discourse.group/t/fictitious-calendar-how-to-create-one/3474>\
**Category:** Help\
**Tags:** worldbuilding\
**Created:** [March 31, 2023, 6:39am UTC](https://gramps.discourse.group/t/fictitious-calendar-how-to-create-one/3474 "2023-03-31T06:39:17Z")\
**Posts on this page:** 1\
**Showing post:** 19

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**Author:** ![GeorgeWilmes](https://avatars.discourse-cdn.com/v4/letter/g/c57346/32.png) [@GeorgeWilmes](https://gramps.discourse.group/u/GeorgeWilmes)\
**Post date:** [April 1, 2023, 9:23pm UTC](https://gramps.discourse.group/t/fictitious-calendar-how-to-create-one/3474/19 "2023-04-01T21:23:54Z")

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> [@Annie.E](#):
>
> things like “Are these people alive at the same time?”

Even with dates that Gramps understands, that particular question is tricky. See [this thread](https://gramps.discourse.group/t/extract-data-between-two-dates/3449).

But, if you use the text-based dates, then I think all you would need to do is code a (relatively) simple custom filter rule that would look for dates (as text strings) that are “between” two given input strings.

In fact, I think such a rule for normal dates would help with the issue in the thread linked above.

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