Cum parentes domum rediissent, mater de monte et valle fabulam narravit.

Here cum introduces a subordinate clause: Cum parentes domum rediissent.

In Latin, cum can mean several things, such as when, since, or although, depending on context and the verb form. In this sentence, it is a temporal/circumstantial cum clause, so it means something like when or after.

Because the verb in the clause is rediissent (pluperfect subjunctive), the sense is:

• when the parents had returned home
• or more naturally in English, after the parents had returned home

So cum here is not the preposition meaning with. It is a conjunction meaning when/after.

This is a very common question, because English does not mark this kind of difference as clearly as Latin does.

In Latin, cum clauses that describe the circumstances surrounding the main action often take the subjunctive, especially in more literary or formal Latin. So:

• cum ... rediissent = when/after they had returned

The subjunctive here does not necessarily make the action doubtful or unreal. It is simply the normal grammar for this kind of cum clause.

If you are learning Latin, it helps to think:

• cum + subjunctive often gives background or circumstances
• the main clause then tells the main event

So the sentence structure is:

• background: when the parents had returned home
• main event: the mother told a story

Rediissent is pluperfect subjunctive active, third person plural.

It comes from redeo, redire, redii/redivi, reditum, meaning to go back, to return.

The pluperfect is used because the returning happened before the mother told the story. In other words:

1. the parents returned home
2. then the mother told a story

So Latin shows this sequence clearly:

• rediissent = had returned
• narravit = told

That is exactly the same time relationship as English had returned before told.

This is one of the most important idioms in Latin.

Domum means home or to home/homeward, and with domus Latin often does not use a preposition for motion toward home.

So:

• domum redire = to return home
• not normally ad domum redire

This is similar to a few other special place expressions in Latin, especially with home, town names, and small islands.

So in this sentence:

• domum rediissent = had returned home

Here domum is an accusative of place to which.

Parentes is nominative plural.

Its role is the subject of rediissent:

• parentes rediissent = the parents had returned

The form parentes could in some contexts also be accusative plural, but here the verb needs a subject, so nominative makes sense.

Mater is nominative singular.

It is the subject of the main verb narravit:

• mater narravit = the mother told

So the sentence has two different subjects in two different clauses:

• parentes = subject of rediissent
• mater = subject of narravit

Fabulam is accusative singular.

It is the direct object of narravit:

• fabulam narravit = she told a story

The verb narrare commonly takes a direct object in the accusative, the thing being told:

• historiam narrare = to tell a story/history
• fabulam narrare = to tell a tale/story

So fabulam answers the question what did the mother tell?

They are in the ablative because they follow the preposition de.

• de monte = about/concerning the mountain or from the mountain, depending on context
• de valle = about/concerning the valley or from the valley

Here, because the mother is telling a story, de means about:

• de monte et valle = about the mountain and the valley

So:

• mons becomes monte in the ablative singular
• vallis becomes valle in the ablative singular

Here de means about or concerning.

That is a very common use of de with verbs of speaking, telling, writing, or thinking.

So:

• de monte et valle fabulam narravit = she told a story about a mountain and a valley

Latin de can also mean down from or from, but that is not the meaning here. The verb narravit makes the about meaning the natural one.

Latin word order is much freer than English word order.

Both of these would make sense:

• de monte et valle fabulam narravit
• fabulam de monte et valle narravit

In your sentence, the prepositional phrase de monte et valle comes before fabulam, perhaps to set up the topic of the story before naming it as a story.

Latin often arranges words for emphasis, rhythm, or style rather than following a fixed English-like order.

So the sentence is not strange; it is simply using normal Latin flexibility.

Narravit is perfect active indicative, third person singular, from narro, narrare.

The perfect tense here expresses a completed past action:

• narravit = told / has told, depending on context

In a narrative sentence like this, the natural English translation is told.

The tense contrast is important:

• rediissent = had returned before the main event
• narravit = told as the main event

So Latin is carefully showing the order of events.

Either can work, depending on how smooth you want the English to sound.

Literally, cum often means when, but because the verb is pluperfect (rediissent = had returned), the sense is that the action was already completed before the mother told the story. So in English, after can sound more natural:

• When the parents had returned home, the mother told a story
• After the parents had returned home, the mother told a story

The second version is often more idiomatic in English, even though Latin still uses cum.

Latin has no articles. There is no direct equivalent of English the or a/an.

So:

• parentes can mean parents or the parents
• mater can mean mother or the mother
• monte can mean a mountain or the mountain
• valle can mean a valley or the valley
• fabulam can mean a story or the story

English has to choose an article when translating, but Latin leaves that to context.

Usually parentes means parents, but like many family words in Latin, it can sometimes be broader depending on context.

In a simple sentence like this, the natural meaning is just the parents. A learner should understand it that way unless context suggests something else.

The dictionary form is redeo, redire, redii (or redivi), reditum.

It is a compound of eo (I go) with re- (back), so it means I go back, I return.

Rediissent breaks down like this:

• redi- = stem from the perfect system
• -issent = pluperfect subjunctive ending for third person plural

So rediissent means they had returned.

A good way to see it is to divide the sentence at the comma:

• Cum parentes domum rediissent, = subordinate clause
• mater de monte et valle fabulam narravit. = main clause

The first clause begins with cum and ends with rediissent. That gives the background situation.

The second clause has its own subject and finite verb:

• subject: mater
• verb: narravit

So once you see cum at the start and a comma after rediissent, it becomes easier to parse the sentence.

Grammatically, de can indeed mean from or down from. But context decides the meaning.

Because the verb is narravit (told), the phrase naturally means about:

• de monte et valle fabulam narravit = she told a story about the mountain and the valley

If the sentence involved movement, then de might mean from. But with a verb of storytelling, about is the right sense.

Yes, several very useful Latin patterns appear here:

• cum + subjunctive for a background/time clause
• pluperfect to show an action completed before another past action
• domum without a preposition for homeward / home
• de + ablative meaning about
• narrare + accusative for tell a story

If you remember those patterns, this one sentence teaches a lot of standard Latin grammar.