Artifex dicit aurum purum esse et se id hodie vendere velle.

This is one of the most common features of Latin syntax: after verbs of saying, thinking, knowing, perceiving, and similar ideas, Latin often uses an indirect statement.

In English, we say:

• The craftsman says that the gold is pure
• The craftsman says that he wants to sell it today

In Latin, instead of a that-clause, you usually get:

• an accusative subject
• plus an infinitive

So:

• aurum purum esse = that the gold is pure
• se id hodie vendere velle = that he wants to sell it today

This construction is often called the accusative-and-infinitive construction.

If this were a direct statement by itself, yes:

• Aurum purum est = The gold is pure

But inside an indirect statement after dicit, the subject of the infinitive goes into the accusative.

So:

• direct: aurum ... est
• indirect after dicit: aurum ... esse

That is why aurum is accusative here: it is the subject of the infinitive esse.

Because purum agrees with aurum.

Since aurum is:

• neuter
• singular
• accusative

the adjective describing it must match:

• purum

So:

• aurum purum esse = that the gold is pure

Even though purum may look like an object to an English speaker, it is actually a predicate adjective agreeing with aurum.

Because this is an indirect statement.

In a direct statement, you would say:

• Aurum purum est = The gold is pure

After dicit, Latin changes the finite verb est into the infinitive esse:

• Artifex dicit aurum purum esse = The craftsman says that the gold is pure

So esse is just the infinitive form corresponding to is.

Se is the reflexive pronoun in the accusative. It refers back to the subject of the main clause, here artifex.

So:

• artifex ... se ... velle = the craftsman says that he himself wants...

If Latin used eum, that would normally refer to some other male person, not back to artifex.

So the sentence means:

• The craftsman says ... that he wants to sell it today

with he = the craftsman.

For the same reason that aurum is accusative: se is the subject of an infinitive in indirect statement.

In:

• se id hodie vendere velle

the verb velle is an infinitive, and the subject of that infinitive is se.

So literally this part is:

• himself to want to sell it today

which in natural English becomes:

• that he wants to sell it today

Id means it and is the accusative singular neuter of is, ea, id.

It is the direct object of vendere:

• vendere id = to sell it

Here id refers back to the gold, aurum.

Since aurum is neuter singular, the pronoun referring to it is also neuter singular:

• id

So:

• se id hodie vendere velle = that he wants to sell it today

Here id makes the object explicit: sell it.

Latin can sometimes omit a pronoun if the meaning is obvious from context, but including id is perfectly normal and often clearer. In this sentence it helps show that what he wants to sell is the gold already mentioned.

So id functions much like an English pronoun referring back to a previous noun.

Because velle means to want, and it is commonly followed by another infinitive telling what someone wants to do.

So:

• vendere = to sell
• velle = to want

Together:

• vendere velle = to want to sell

Then because this whole idea is in indirect statement after dicit, the whole phrase appears as part of:

• se id hodie vendere velle = that he wants to sell it today

It helps to unpack it piece by piece:

• se = the subject of velle in accusative, he / himself
• velle = to want
• vendere = infinitive depending on velle, to sell
• id = object of vendere, it
• hodie = today

So literally:

• himself it today to sell to want

Better English:

• that he wants to sell it today

This is a nested structure:

1. se ... velle = that he wants
2. id vendere = to sell it

Put together:

• that he wants to sell it

In indirect statement, the tense of the infinitive shows time relative to the main verb, not necessarily an English-style absolute tense.

Here both esse and velle are present infinitives, which usually indicate action or state happening at the same time as the main verb dicit.

So:

• dicit ... aurum purum esse = he says that the gold is pure
• dicit ... se id hodie vendere velle = he says that he wants to sell it today

Since dicit is present, English naturally uses present verbs too.

Et simply joins two parallel indirect statements after dicit:

1. aurum purum esse
2. se id hodie vendere velle

So the structure is:

• Artifex dicit [A] et [B].

That means:

• The craftsman says [that A] and [that B].

Latin often states dicit once and then coordinates multiple accusative-and-infinitive clauses after it.

Latin word order is more flexible because the endings show the grammatical relationships.

English depends heavily on order:

• The craftsman says that the gold is pure and that he wants to sell it today.

Latin can arrange words more freely:

• Artifex dicit aurum purum esse et se id hodie vendere velle.

A few tendencies are still visible:

• the main verb dicit comes fairly early
• the infinitives often come toward the ends of their phrases
• important words can be placed for emphasis

But the endings, not the order alone, tell you how the sentence works.

Artifex is nominative singular and is the subject of dicit.

Its basic meaning is something like:

• craftsman
• artisan
• maker

So:

• Artifex dicit = The craftsman says

It is a third-declension noun, which is why the nominative singular ends in -ex.

Yes. If you turn the indirect statements into direct statements, you would get something like:

• Aurum purum est et id hodie vendere volo, if the craftsman himself were speaking in the first person: The gold is pure and I want to sell it today.

Or, if you keep it as a third-person report without direct quotation content adjusted for speaker perspective, the underlying direct statements are roughly:

• Aurum purum est
• Id hodie vendere vult

The Latin sentence combines those ideas into indirect statement after dicit:

• Artifex dicit aurum purum esse et se id hodie vendere velle.

In a sentence like this, se normally refers back to the subject of the clause it belongs to, here the subject of dicit, namely artifex.

So the reflexive is not just nearest noun = automatic reference. It is tied to grammatical structure.

That is why:

• se = the craftsman himself

If Latin wanted to say that the craftsman says another man wants to sell it, it would usually use a non-reflexive pronoun or noun instead.