In horreo multae merces servantur, et vinum in dolio magno manet.

Because in takes the ablative when it means in / on / at in the sense of location.

• in horreo = in the warehouse / in a warehouse
• This answers where?

By contrast, in takes the accusative when it shows motion into something:

• in horreum = into the warehouse

So here, since the goods are already there, Latin uses in + ablative.

horreo comes from horreum, horrei (neuter), meaning storehouse, granary, warehouse.

It is ablative singular:

• nominative: horreum
• ablative: horreo

That ablative is used after in for location: in horreo.

Because merces is a feminine noun here, so the adjective must agree with it in:

• gender
• number
• case

So:

• merces = feminine plural nominative
• multae = feminine plural nominative

That is why Latin uses multae, not multi.

Here it is definitely plural.

You can tell because:

• multae is plural
• servantur is plural

So multae merces servantur means many goods are stored.

This can confuse learners because merces is one of those third-declension nouns whose nominative singular and nominative plural can look the same. The surrounding words tell you which it is.

Because the sentence is describing what happens to the goods, not what the goods are doing.

• servant = they store
• servantur = they are stored / kept

Here merces is the subject, but it is receiving the action:

• multae merces servantur = many goods are stored

So the passive is the natural choice.

servantur comes from servo, servare, which can mean:

• save
• preserve
• keep
• store

In this context, store/keep fits best.

Form breakdown:

• serva- = verb stem
• -ntur = third person plural passive

So servantur means they are kept/stored.

In second-declension neuter nouns, the nominative singular and accusative singular are the same.

So vinum can be either:

• nominative singular = wine as subject
• accusative singular = wine as object

Here it is nominative because it is the subject of manet:

• vinum ... manet = the wine remains

A helpful rule: in neuter nouns, nominative and accusative are always identical.

Because in is again showing location, so it takes the ablative. The adjective must agree with the noun.

• dolio = ablative singular of dolium
• magno = ablative singular of magnus

So:

• in dolio magno = in the large jar / barrel

Both words are ablative because they belong together in the same phrase.

Latin word order is much freer than English word order. Both of these are possible:

• in dolio magno
• in magno dolio

The adjective can come before or after the noun. Often the choice depends on style, emphasis, or what sounds natural in the sentence.

So dolio magno does not mean anything different from magno dolio here; it is just a normal Latin word order.

manet means more than simply is. It means:

• remains
• stays
• continues to be

So:

• vinum in dolio magno manet = the wine remains/stays in the large jar

If Latin used est, that would simply say the wine is there. manet emphasizes continued presence.

Because Classical Latin does not have articles like English the and a/an.

So a phrase like:

• in horreo can mean in the warehouse or in a warehouse
• vinum in dolio magno can mean the wine in the large jar or wine in a large jar

The exact sense depends on context. Latin leaves that unstated unless something else makes it clear.

Latin relies much more on endings than on word order to show who is doing what. That gives Latin more freedom in arranging words.

This sentence begins with in horreo, which puts the setting first:

• In horreo = in the warehouse
• then the subject: multae merces
• then the verb: servantur

A very literal order would be:

• In the warehouse many goods are stored, and the wine in the large jar remains

English usually prefers a more fixed order, but Latin can move things around for emphasis or style without changing the basic meaning.