Si praesidium paratum est, urbs servari potest.

Si means if.

It introduces the condition:

• Si praesidium paratum est = If the defense/garrison is ready

Then the main clause gives the result:

• urbs servari potest = the city can be saved

So the basic pattern is:

• si
  • condition
• main clause + result

This is very similar to English if ... , then ..., except Latin often leaves out any separate word for then.

Praesidium is a neuter noun. Depending on context, it can mean things like:

• protection
• defense
• guard
• garrison
• detachment of troops

In this sentence, it most naturally means something like the defense or the garrison/guard force.

Latin words often have a range of meanings, so the exact English choice depends on context.

Because paratum agrees with praesidium.

• praesidium is neuter singular
• so the adjective or participle describing it must also be neuter singular
• therefore: paratum

Agreement in Latin usually means matching:

• gender
• number
• case

So:

• masculine singular: paratus
• feminine singular: parata
• neuter singular: paratum

In this sentence, paratum est means is ready or has been prepared, depending on context.

Here is the form:

• paratum = perfect passive participle of parare (prepare)
• est = is

Literally, it is something like has been prepared. But in many contexts, that naturally becomes is prepared or is ready in English.

So praesidium paratum est can be understood as:

• the defense has been prepared
• the defense is prepared
• the defense is ready

The meaning shown to the learner will tell you which English version is best.

Urbs is nominative because it is the subject of the main clause.

The main clause is:

• urbs servari potest

Literally:

• the city can be saved

Even though English speakers may first think of save the city, Latin here uses the passive:

• active: someone can save the city
• passive: the city can be saved

In the passive version, the city becomes the subject, so Latin uses the nominative:

• urbs = nominative singular

Servari is the present passive infinitive of servare.

So:

• servare = to save (active infinitive)
• servari = to be saved (passive infinitive)

This is a very common pattern with first-conjugation verbs:

• active infinitive: -are
• passive infinitive: -ari

Examples:

• amare = to love

• amari = to be loved

• servare = to save
• servari = to be saved

Because the passive idea is already built into servari.

In English, we say:

• can be saved

That has two parts:

• be
• saved

In Latin, the passive infinitive servari already means to be saved, so Latin does not need a separate word for be here.

Then potest adds the idea of can:

• servari potest = can be saved

Potest means is able or can. It often takes an infinitive, just like English can or to be able to.

So:

• potest servare = he/she/it can save
• potest servari = he/she/it can be saved or it can be saved

In this sentence:

• urbs servari potest = the city can be saved

This is a very common construction in Latin:

• possum, potes, potest...
  • infinitive

Because this is a straightforward, real possibility condition.

The sentence says, in effect:

• If the defense is ready, the city can be saved.

Latin commonly uses the indicative for simple or open conditions like this, where the speaker is not presenting the condition as impossible or purely hypothetical.

So we get:

• si praesidium paratum est
  with est in the indicative

A learner will later meet subjunctive conditions too, but this sentence is a basic, factual kind of if statement.

The main finite verbs are both present tense:

• est = is
• potest = can / is able

The infinitive servari is a present passive infinitive.

Even though paratum est uses a perfect passive participle, the whole expression can still be translated naturally as a present-state idea:

• is prepared
• is ready

So the overall sense of the sentence is present-time:

• If the defense is ready, the city can be saved.

The word order is normal and clear, but Latin word order is more flexible than English.

Here the sentence is arranged as:

• Si praesidium paratum est = the condition first
• urbs servari potest = the result second

That is a very natural order in both Latin and English.

Within the clauses, Latin can move words around more freely because the endings show their roles. For example, urbs is clearly the subject because of its form, even if the words were rearranged.

Still, the given order is neat and readable:

• condition first
• main statement after it

Yes. Praesidium can refer either to:

• the abstract idea of protection/defense or
• the people or force providing that protection, such as a guard or garrison

So depending on context, the sentence might suggest:

• If the defense is ready, the city can be saved or
• If the garrison is ready, the city can be saved

Both are possible meanings of the Latin word. Context decides which is best.

Yes, grammatically that is possible.

Because paratum est can mean:

• is ready / is prepared or
• has been prepared

So a more literal reading could be:

• If the garrison/defense has been prepared, the city can be saved

But in many textbook sentences, the smoother English meaning is simply:

• If the defense is ready, the city can be saved

Both come from the same Latin structure; context determines which shade is intended.