Murmillo se defendit sicut lanista eum docuit.

There is no separate word here because Latin has no articles.

So:

• Murmillo can mean the murmillo or a murmillo
• lanista can mean the trainer or a trainer

English has to supply the or a from context.

Latin usually shows that through case endings and verb forms, not mainly through word order.

In this sentence:

• Murmillo is the subject of defendit
• se is the object of defendit
• lanista is the subject of docuit
• eum is the object of docuit

So the sentence has:

• a main clause: Murmillo se defendit
• a subordinate clause: sicut lanista eum docuit

Se is the reflexive pronoun. It means himself / herself / itself / themselves, depending on context.

A reflexive pronoun points back to the subject of its own clause.

So in Murmillo se defendit:

• subject = Murmillo
• object = se
• therefore Murmillo is defending himself

If Latin used eum there instead, it would mean he defended him, meaning some other male person.

Because reflexives in Latin normally refer to the subject of their own clause, not to a subject in a different clause.

In sicut lanista eum docuit:

• the subject of docuit is lanista
• so se in that clause would refer to lanista

That means:

• lanista se docuit = the trainer taught himself
• lanista eum docuit = the trainer taught him

So Latin uses eum to refer back to Murmillo, because se would point to the wrong person.

This is a very common thing for English speakers to notice, because English is less strict about this kind of clause-by-clause reflexive reference.

Sicut means as, just as, or in the way that.

It introduces a clause explaining the manner of the action:

• Murmillo se defendit = the main action
• sicut lanista eum docuit = tells how he did it

So the idea is that he defended himself in the way the trainer had taught him.

Docuit is the third person singular perfect active indicative of docere, meaning to teach.

So docuit means:

• taught
• or sometimes has taught, depending on context

Here the subject is lanista, so lanista eum docuit means that the trainer taught him.

It can be either one in writing.

Defendit can mean:

• he defends — present
• he defended or has defended — perfect

This is a normal ambiguity in Latin for some verbs.

So you decide from context. If the meaning already given to the learner is past, then you read it as perfect. If the context is describing what he does, then it could be present.

Not by itself. Se is not marked for masculine vs feminine the way English himself / herself is.

It can mean:

• himself
• herself
• itself
• themselves

The context tells you which English form to use.

Here, because Murmillo is singular and masculine, se is translated as himself.

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

English depends heavily on order:

• The trainer taught him is different from He taught the trainer

Latin depends more on endings, so it can move words around more freely.

This sentence uses a very natural Latin arrangement:

• main clause first
• then the sicut clause
• with docuit placed at the end of its clause, which is common in Latin

You could rearrange the words without changing the basic meaning, but the emphasis would change. Latin word order often helps show focus, rhythm, or style rather than basic grammar.