It has forms and functions derived from the Proto-Indo-European ablative, instrumental, and locative.
[1] It is sometimes called the adverbial case, since phrases in the ablative can be translated as adverbs: incrēdibilī celeritāte, 'with incredible speed', or 'very quickly'.
Some meanings of the ablative descend from the Proto-Indo-European locative case.
The ablative case is very frequently used with prepositions, for example ex urbe "out of the city", cum eō "with him".
Four prepositions (in "in/into", sub "under/to the foot of", subter "under", super "over") may take either an accusative or an ablative.