latindate

This is a utility, written in C99, that displays a timestamp in Latin using the inclusive counting style of the Roman calendar (and with Roman numerals displayed properly using the Roman numeral glyphs from the Number Forms Unicode block).

It is regularly tested on IBM AIX and Linux (using both glibc and musl).

$ date
Thu Jun 26 10:53:02 PM EDT 2025

$ latindate          
ultimum·​recognitum·​est·​ante·​diem·​Ⅵ·​kalendas·​iulias·​anno·​domini·​ⅯⅯⅩⅩⅤ

The text translated to English reads…

Last revised on the sixth day before the kalends of July in the year of our Lord 2025

…or, more succinctly:

Last revised June 26 2025

The Latin text is output in lower case, with words delimited by interpunct (·) characters, followed by Unicode zero-width space characters, for easier post-processing. Ligatures are used where appropriate. Easter and Christmas have specific handling.

If you want to generate the Latin text for arbitrary dates, libfaketime comes in handy:

$ faketime -m 2032-03-28 latindate
ultimum·​recognitum·​est·​die·​paschæ·​ante·​diem·​Ⅴ·​kalendas·​aprilis·​anno·​domini·​ⅯⅯⅩⅩⅩⅡ

The output itself is intended to be rendered using small capital glyphs, but if you prefer regular capitals, you can leverage tr for the conversion:

faketime -m 2032-03-28 latindate | tr '[:lower:]' '[:upper:]' | tr 'æ' 'Æ'
ULTIMUM·​RECOGNITUM·​EST·​DIE·​PASCHÆ·​ANTE·​DIEM·​Ⅴ·​KALENDAS·​APRILIS·​ANNO·​DOMINI·​ⅯⅯⅩⅩⅩⅡ

For an example of this program in action, check out the timestamps on the Illuminationes web page.