Magistratus centuriam in tabulario scribit.

Because magistratus is in the nominative case, which is the case normally used for the subject of a sentence.

A beginner-friendly point: even though -us often makes English speakers think of the second declension, magistratus is actually a fourth-declension noun. Its nominative singular is still magistratus.

Also, the verb scribit is singular, so here magistratus must be understood as one magistrate, not more than one.

Yes, in form it could. In the fourth declension, magistratus can be either:

• nominative singular = a magistrate
• nominative plural = magistrates

So how do we tell which one it is here? By the verb.

• scribit = he/she/it writes = singular
• if the subject were plural, you would expect scribunt = they write

So in this sentence, magistratus is singular.

Because centuriam is in the accusative singular. The accusative case is usually used for the direct object of the verb.

Here, the magistrate is doing the action of writing, and centuriam is the thing being written or recorded. That is why it appears in the accusative.

Its basic form is centuria. The forms are:

• centuria = nominative singular
• centuriam = accusative singular

Tabulario is ablative singular.

After in, Latin can use two different cases:

• in + ablative = in, on, at a place
• in + accusative = movement into a place

So:

• in tabulario = in the record office / archive
• in tabularium would mean into the record office / archive

In this sentence there is no movement into the place; it just tells you where the writing happens, so Latin uses the ablative.

The dictionary form is tabularium, a second-declension neuter noun.

So:

• tabularium = nominative singular
• tabulario = ablative singular

Because it follows in in a location sense, you get in tabulario.

Scribit comes from scribere, meaning to write.

The ending -it tells you that it is:

• third person
• singular
• present tense
• active voice
• indicative mood

So scribit means he writes, she writes, or it writes. Since the subject here is magistratus, the sense is the magistrate writes.

Classical Latin does not have definite or indefinite articles like English the and a/an.

So a noun such as magistratus can mean:

• a magistrate
• the magistrate

Likewise, centuriam can mean:

• a century / a centuria
• the century / the centuria

Which one sounds best depends on the context or the translation you have been given.

Because Latin word order is much more flexible than English word order.

Latin often puts the verb near the end, especially in straightforward prose, so Magistratus centuriam in tabulario scribit is a very natural arrangement.

But the case endings already show the jobs of the words, so other orders are also possible, for example:

• Centuriam magistratus in tabulario scribit
• In tabulario magistratus centuriam scribit

The emphasis may shift slightly, but the basic meaning stays the same.

In Latin, you often rely more on endings than on position.

Here the endings tell you the structure:

• magistratus = nominative subject
• centuriam = accusative direct object
• tabulario = ablative after in, showing location
• scribit = singular verb

So even if the words move around, the endings still tell you who is doing the action and what is being acted on.

It most naturally goes with scribit and tells you where the writing takes place.

So the sense is:

• the magistrate writes/records the centuria
• in the record office / archive

In other words, in tabulario is functioning as a location phrase for the verb, not as a description of centuriam.