Post longum iter Romam redimus, et Tiberis sub ponte lente fluit.

Because the preposition post takes the accusative case. Here it means after, so longum iter is its object.

• iter = journey
• longum = long, agreeing with iter in case, number, and gender
• iter is a neuter noun, so the adjective is neuter too

A useful detail: iter is a 3rd-declension neuter noun (iter, itineris), and its nominative and accusative singular are both iter.

Because iter is neuter, not masculine. Latin adjectives must agree with the noun they describe in:

• gender
• number
• case

So if iter is neuter singular accusative, the adjective must also be neuter singular accusative: longum.

With names of cities and small islands, Latin often uses the accusative without a preposition to show motion toward a place. This is called the accusative of place to which.

So:

• Romam redimus = we return to Rome

Using ad is normally unnecessary with city names.

Redimus is:

• 1st person plural
• present indicative active
• from redeo, redire = to go back, return

So it means we return or sometimes we are returning, depending on context.

It is a compound of eo (I go), so its forms can look a little less regular than a standard 1st-conjugation verb.

Because the verb ending already tells you the subject.

In redimus, the ending -mus means we. So Latin usually does not need an expressed pronoun unless it is being emphasized.

• redimus = we return
• nos redimus = we return with extra emphasis on we

Because Tiberis is the subject of fluit.

In the clause Tiberis sub ponte lente fluit, the river is the thing doing the action of flowing, so it must be in the nominative case.

Tiberis is the nominative singular form of the river’s name. Its accusative would be Tiberim.

Because sub can take two different cases, depending on the meaning:

• ablative = location, under
• accusative = motion toward a position under something

Here sub ponte means under the bridge as a location, so Latin uses the ablative.

Compare:

• sub ponte fluit = it flows under the bridge
• sub pontem currit = it runs to a position under the bridge

Ponte is ablative singular of pons, pontis, meaning bridge.

So in sub ponte, the ablative is used because of sub with the meaning of location.

Lente is an adverb, not an adjective. It modifies the verb fluit and means slowly.

It comes from the adjective lentus, -a, -um, meaning slow or calm. A common way to form adverbs from 1st/2nd-declension adjectives is with -e:

• lentus = slow
• lente = slowly

So lente fluit means flows slowly.

Latin word order is much more flexible than English word order because Latin uses case endings to show how words function in the sentence.

So Latin can move words around for:

• emphasis
• rhythm
• style
• clarity

For example:

• Romam redimus places Romam before the verb
• Tiberis sub ponte lente fluit places the verb at the end, which is very common in Latin

Even though the order changes, the endings tell you who is doing what.

Classical Latin has no definite or indefinite articles like the or a/an.

So Latin simply says:

• Tiberis
• pons / ponte

and English adds the if the context requires it. That is why Tiberis can be translated as the Tiber, and ponte as the bridge, even though Latin has no separate word for the.

Yes. Both redimus and fluit are present tense forms:

• redimus = we return / we are returning
• fluit = it flows / is flowing

Latin present tense can often be translated in more than one natural English way, depending on context. English sometimes prefers a simple present and sometimes a progressive form, but Latin uses the same present tense form for both possibilities.