It's probably safe to use these names, but I do want to make sure. I would like to say, in Latin, How would the Romans have said this during the late Roman republic (or the early empire)?
Even though the Gregorian calendar replaced the Julian calendar, did the manner of stating the date in Latin change over all these centuries?
In contemporary Latin, it is common to write things in a more simple and modern way: "on January 5" is simply .
Again, ellipsis is possible if this feels too verbose.
For example, I'll L-A-space, and get ላ or H-I-space and get ሂ.