Cum matri non placeret illa opinio, filia tamen auctoritati magistri confidebat.

Because this cum introduces a subordinate clause with the subjunctive, not the preposition meaning with.

In this sentence, cum matri non placeret illa opinio means something like since / although that opinion did not please the mother. Latin very often uses cum + subjunctive for background circumstances, cause, or concession in past narration.

So:

• cum = when / since / although depending on context
• placeret = imperfect subjunctive, used because of this kind of cum clause

Here, because the main clause has tamen (nevertheless), many learners will understand the clause as especially close to although:

• Although that opinion did not please the mother, the daughter nevertheless trusted the teacher's authority.

It could be understood in more than one way, but although is especially natural here because of tamen in the main clause.

A useful guide:

• cum + subjunctive can express:
  • time/background: when
  • cause: since / because
  • concession: although

Because the second clause contains tamen (however / nevertheless), Latin is signaling a contrast. That makes a concessive sense very likely:

• Although that opinion did not please the mother, the daughter nevertheless trusted the teacher's authority.

Without tamen, since or when might feel more possible.

Because placeo works differently from English please.

In Latin, placeo takes:

• the thing that is pleasing as the subject
• the person pleased as the dative

So in matri non placeret illa opinio:

• illa opinio = that opinion → subject
• matri = to the mother → dative
• literally: that opinion was not pleasing to the mother

A very literal English gloss would be:

• That opinion did not please the mother or even
• That opinion was not pleasing to the mother

This is a very common Latin pattern.

Because the verb placeo is built so that the thing liked or disliked is the grammatical subject.

So:

• illa opinio = nominative singular feminine → subject
• matri = dative singular → the person affected

English often makes the person seem more central:

• The mother did not like that opinion

But Latin expresses it as:

• That opinion was not pleasing to the mother

That is why opinio, not mater, is the subject.

There are two reasons:

1. It is inside a cum clause that regularly takes the subjunctive in this kind of sentence.
2. The imperfect shows action going on in past time relative to the main verb.

The main verb is confidebat (was trusting / trusted), also in past time. The imperfect subjunctive in the cum clause gives background information that is simultaneous with the main action:

• while / since / although the opinion was not pleasing to the mother,
• the daughter was trusting the teacher's authority.

So placeret is not random; it fits both the syntax of cum and the past-time setting.

Because they belong to different kinds of clauses.

• confidebat is the main verb of the main clause, so it is in the indicative
• placeret is in a subordinate cum clause, which here takes the subjunctive

So the contrast is structural:

• Main statement: filia ... confidebat
• Background/concessive clause: cum ... placeret

This is a very common Latin pattern: the main clause states the event directly, while the cum clause gives the surrounding circumstance in the subjunctive.

Because confido commonly takes the dative of the person or thing trusted.

So:

• auctoritati = to the authority
• magistri = of the teacher

Together:

• auctoritati magistri = to the teacher's authority or more naturally in the teacher's authority

A literal rendering of confidere alicui rei is:

• to trust in something or
• to have confidence in something

This is another place where Latin uses the dative in a way that may feel unusual to English speakers.

Because the verb is confidebat, from confido, and confido does not normally take a direct object in the accusative here. It takes the dative.

So Latin says:

• auctoritati magistri confidebat = she trusted the teacher's authority

Not:

• auctoritatem magistri confidebat

That accusative would not fit the normal construction of confido in this sentence.

A good habit for learners is to memorize some verbs together with the case they govern:

• placeo + dative
• confido + dative

Magistri is genitive singular, meaning of the teacher.

It depends on auctoritati:

• auctoritas = authority
• auctoritati magistri = to the authority of the teacher

In smoother English, that becomes:

• the teacher's authority

So this is a standard possessive genitive.

Tamen means nevertheless, still, or however.

Its job here is to mark a contrast between the two clauses:

• the opinion did not please the mother,
• yet / nevertheless the daughter trusted the teacher's authority.

That is why tamen strongly supports reading cum in a concessive sense:

• Although the opinion did not please the mother, the daughter nevertheless trusted the teacher's authority.

Without tamen, the contrast would be weaker.

Latin word order is much more flexible than English word order because Latin endings show the grammatical roles of words.

In this sentence:

• Cum matri non placeret illa opinio
• filia tamen auctoritati magistri confidebat

The endings tell you what each word is doing:

• matri = dative
• opinio = nominative
• filia = nominative
• auctoritati = dative
• magistri = genitive

Because those endings carry so much information, Latin can place words for emphasis, balance, or style rather than relying mainly on position.

For example:

• matri comes early, which gives prominence to the mother
• illa opinio comes later, even though it is the subject of the subordinate clause
• tamen sits near the start of the main clause to highlight the contrast

At the basic level, illa simply means that and agrees with opinio:

• feminine
• singular
• nominative

So:

• illa opinio = that opinion

Depending on context, ille, illa, illud can sometimes feel slightly emphatic, like that particular or that well-known. But in a sentence like this, the safest reading is just that opinion.

Yes, in principle. Latin often omits subject pronouns, and sometimes even a noun subject can be omitted if the context makes it clear.

But here filia is useful because it clearly names who was doing the trusting:

• the daughter

If the sentence only had confidebat, the verb ending would tell us he/she/it was trusting, but not which person specifically. So filia is included for clarity and probably also for contrast with matri.

A very literal breakdown is:

• Cum = although / since / when
• matri = to the mother
• non placeret = was not pleasing
• illa opinio = that opinion
• filia tamen = the daughter nevertheless
• auctoritati magistri = to the authority of the teacher
• confidebat = was trusting / trusted

So a very literal version would be:

• Although that opinion was not pleasing to the mother, the daughter nevertheless trusted the teacher's authority.

That literal phrasing helps show the Latin grammar, especially:

• placeo + dative
• confido + dative
• magistri as a genitive
• cum + subjunctive for the subordinate clause