How is time period expressed in Latin?

Question

How is time period expressed in Latin, e.g. "from Jan 1 to Mar 31"?

I notice there are two prepositions meaning "from", "ab" and "ex". What's their difference? Which should I use for time period?

Answer 1

Both ex and ab can be used for specific dates. Here are two examples from Cicero's Epistulae ad Atticum; the first uses ex, and the second uses a(b). For the upper limit of the range, ad or usque ad can be used, as shown here; I believe I've also seen in (+ accusative) used.

3.17.1:

de Quinto fratre nuntii nobis tristes nec varii venerant ex a. d. iiii. Non. Iun. usque ad prid. Kal. Sept. eo autem die Livineius, L. Reguli libertus, ad me a Regulo missus venit.

...from four days before the Nones of June all the way to the day before the Kalends of September...

2.8.2:

sed cognosce itinera nostra ut statuas ubi nos visurus sis. in Formianum volumus venire Parilibus. inde, quoniam putas praetermittendum nobis esse hoc tempore Cratera illum delicatum, Kal. Mai. de Formiano proficiscemur, ut Anti simus a. d. v. Non. Mai. ludi enim Anti futuri sunt a iiii. [Kal.] ad prid. Non. Mai. eos Tullia spectare vult.

...from four days before to the day before the Nones of May...