Dates “before the common era”, can be entered with the suffix BCE.
Technical Note 1: This feature will export and import from GEDCOM, but isn’t often used in western genealogy, so isn’t well tested.
[1] The New Oxford Style Manual, Oxford University Press, p.201-203.
[2] A Practical Guide to Dating Systems for Genealogists, Kenneth K. Smith.
[3] Dates and Calendars for the Genealogist, Cliff Webb.
[4] The Gedcom Standard Release 5.5.1, Family History Department, The Church of Jesus Christ of the
Latter-day Saints, 15 November 2019.
[5] The FamilySearch GEDCOM Specification, 7.0.15, The Church of Jesus Christ of the Latter-day Saints, 3 September 2024.