It is a very "special" shopkeeper, considering the other meaning of "caupona": lupanar and cabaret.
I would have thought that inns ( = places for travelers to stay the night when away from their homes) would be out along the routes on which they travel.
But if cauponae include 'boarding establishments' for people to live in temporarily (instead of getting an apartment?), then I suppose they would be in the forums, along with the government offices and stores and such. (Expensive real-estate, I'd have thought.)
Lewis & Short also say that caupona is a synonym of taberna , so, a retail store; such as would be found in a business district, after all.
There's also the (deponent) verb cauponor, cauponari , "to traffic or trade (in any thing)".
The root of caupo- and related words was borrowed from Latin into Germanic, at an obviously early stage, and is the source of the verb kaufen, to buy, and Kaufmann, which I take it means "tradesman" or the like.
Update: Duolingo will also take "shops" for cauponas in this sentence, but not, alas, "stores." In some forms of English, "stores" is the normal word (and around where I live, when a shopping mall wants to appear 'upscale,' they claim to have 'shops,' sometimes spelled 'shoppes.').
HI, Perce_Neige, I'm not sure why you think I'm downvoting your comments. I have no problem with the info. you provide about the lupanar meaning of caupona! (I don't downvote other people's comments; I only upvote them and/or give them a lingot. --Just upvoted the lupanar comment, by the way!)
From my observation, you like to post comments here with information you think is relevant and helpful.
That's the spirit in which I post comments, too.
@Suzanne Lewis & Short is really good, but doesn't give all the meanings for all the words. It's not because they were retail stores, that the word couldn't be used with another connotations. It's not because a word has an etymology, that it can't be used colloquially to mean something else. (Can you say that all the colloquial words in English have only one meaning, and obey to their etymology, or they are rather "hacked" words?)
Tell Wikipedia they are wrong: https://fr.wikipedia.org/wiki/Lupanar_(Pompéi) (I didn't want to link this because of the topic, but as you downvote the comment, I show you a proof).
Des prestations sexuelles étaient également offertes dans des tavernes, habituellement dans 1 ou 2 pièces à l'arrière ou à l'étage supérieur. Citons par exemple la Caupona de Soterius (Regio I, 12, 3), une Caupona avec logement (Regio I, 10, 2) ou la Caupona de Asellina (Regio IX, 11, 2). Dans cette dernière, comme c'est souvent le cas, il y avait aussi de la publicité électorale pour les candidats à des fonctions politiques. Un autre b*rdel, dans une maison, est probablement la Casa degli Amanti
Do you think they were selling what in that kind of "caupona"?
I don't think that "on the market" works here.
"On the market" in English primarily means that something is available for purchase. It's an idiom.
"We plan to put our house on the market in July."
I think this sentence is simply saying that the inns are physically located within a city forum in the Roman empire.
"At the market" and "in the market" are good for simple location, so they could work here, I guess.
But be aware that there are idiomatic meanings in modern English for "at the market" and "in the market" as well.