Can you give examples of the two?

My apologies, it looks like there's already a discussion about this issue (https://forums.zotero.org/discussion/79604/classical-sources) and that there's currently no solution.

Currently, I see two options:

Either:
- cite ancient authors manually in the notes
- add the editions you've consulted as normal books to the bibliography. (Possibly, you will want to have a separate bibliography for ancient works, anyway.)

Or:
- cite everything in the same style. That will give you Hérodote 1936.
- Search/Replace when everything is done.

I am working on IFAO style with the same problem.
A possible solution (at least in bibliography):
It is needed to consider that ancient sources are books that have an author and an editor or a translator.
Then two true/false tests:
<else-if type="book">
<choose>
<if variable="author">
<choose>
<if variable="editor translator" match="none">
<text macro="normal-book"/>
</if>
<else>
<text macro="edited-ancient-sources"/>
</else>
</choose>
</if>
<else>
<text macro="normal-book"/>
</else>
</choose>
</else-if>

The same tests might be used on the way the publication year is rendered, using, for ancient sources, the short title of the book instead of the year.
But this solution is problematic with e.g. posthumously edited books.
All of this would be @maier.de 's first solution

The best solution for this sort of situation will be once a `classic` item exists, to use that. For now, the other conditional I would suggest would be to test for `archive` or `archive-place` to indicate an ancient book in an archive, rather than based on `original-author`.

@maier.de Two uses I’ve thought of for original-author are here https://github.com/citation-style-language/documentation/issues/55

Some discussion related to it being used as a classical author is here https://forums.zotero.org/discussion/82698/old-zotero-interface-in-current-word#latest

As per @bwiernik, the best solution would be to use a `classic` item type, which at the moment exists only in the extended CSL-M syntax.

You can, however, use that in Zotero as well. If the style is for your personal use only (i.e., you don't intend to upload the style to the styles repository), you can just add `type: classic` to the extra field. Zotero will give you a warning when you install a style that uses such non-standard fields or item types, but it will work nevertheless. The citation processor will pick it up, and process citations accordingly. (You could even invent new item types.)

Thank you for your answers.

I am also working on the IFAO style, so I cannot use a solution only available for me.

We cannot use the presence of a translator to distinguish ancient sources because as I previously said, there's also contemporary books with translator and this information should be given in the bibliography. There's also ancient sources in our languages (as the category "Relation de voyage" of the IFAO style).

My idea was to create "hybrid" reference mixing contemporary and ancient books. The standard Zotero fields will be used to add the information on the book and the extra field to add information on the ancient source (original-title and original-author). It will give something like this:
[
{
"id": "http://zotero.org/users/4597224/items/6SGFQVQZ",
"type": "book",
"event-place": "Paris",
"note": "original-author: Hérodote\noriginal-title: Ἱστορίαι",
"publisher-place": "Paris",
"title": "Hérodote. Histoires. Livre I. Clio",
"editor": [
{
"family": "Legrand",
"given": "Philippe-Ernest"
}
],
"issued": {
"date-parts": [
[
"1942"
]
]
}
}
]


But I am not sure if it is correct.