PLACE AND TIME
Latin uses different noun cases in expressions of place and time. This is a handy list you can refer to.
Time within which: Ablative – adveniam paucis horis “I’ll arrive in a few hours”
Time when: Ablative – illo tempore “at that time …”
Time how long: Accusative – ibi habitavi multos annos “I lived there for many years”
Place where: Locative* – sum Romae “I’m in Rome”
Place to where: ad + accusative – eo ad urbem “I’m going to the city”
Place from where a/ab + ablative – veni ab urbem “I’ve come from Rome”
*the locative case is an old case that survives in names of places, expressing where someone or something is. For 1st declension nouns it is identical in form to the genitive (Romae). For 2nd declension nouns it is identical to the ablative (Athenis). Look out also for these three common examples: domi “at home,” ruri “in the country,” humi “on the ground.”