Testamentum non modo coheredem non ostendit, sed ne substitutionem quidem continet.

The sentence has one subject and two coordinated verbs:

• Subject: testamentum = the will
• First verb: ostendit = shows / names / indicates
• Second verb: continet = contains

So the skeleton is:

• Testamentum ... non ostendit, sed ... continet
• The will ... does not show, but ... contains

The two objects are:

• coheredem after ostendit
• substitutionem after continet

The linking pattern is:

• non modo ... sed ...
• not only ... but also / but even ...

So the sentence is built as a contrast:

• the will not only does not name a co-heir
• but does not even contain a substitution

Testamentum is nominative singular neuter.

It is nominative because it is the subject of the sentence: the thing doing the verbal actions of ostendit and continet.

A learner might notice that testamentum ends in -um, which often signals either:

• nominative singular neuter, or
• accusative singular masculine/neuter

Here it must be nominative because it is the subject.

Its dictionary form is:

• testamentum, -i, n. = will, testament

They are in the accusative singular because they are direct objects.

• ostendit coheredem = shows / names a co-heir
• continet substitutionem = contains a substitution

In Latin, direct objects of active transitive verbs are normally in the accusative.

So:

• coheres, coheredis becomes coheredem
• substitutio, substitutionis becomes substitutionem

A native English speaker may not expect this because English usually shows object function mainly by word order, but Latin shows it mainly by case endings.

Coheredem is from coheres, coheredis, meaning co-heir or joint heir.

This is a legal term:

• heres = heir
• coheres = co-heir, someone inheriting together with another heir

So coheredem non ostendit means that the will does not identify or designate a person as a joint heir.

For a learner, it is useful to see the parts:

• co- = together, jointly
• heres = heir

Substitutionem comes from substitutio, substitutionis, meaning substitution.

In legal Latin, this often refers to the appointment of a substitute heir or some provision that one person is to take the place of another under certain conditions.

So here it is not just a vague modern idea of substitution. It is likely a specific testamentary/legal provision.

That is why continet substitutionem means something like:

• contains a substitution clause
• contains a provision for substitution
• contains the appointment of a substitute heir

Non modo ... sed ... is a standard Latin correlative expression meaning:

• not only ... but ...
• often more fully, not only ... but also ...

In this sentence:

• non modo coheredem non ostendit
• sed ne substitutionem quidem continet

This means the second part adds something even stronger. The sense is:

• The will not only fails to name a co-heir, but it does not even contain a substitution.

Latin often uses this pattern to move from one point to a stronger or more surprising point.

This is a very common point of confusion.

In non modo coheredem non ostendit, the first non belongs to the idiom non modo = not only.

The second non is the actual negation of the verb ostendit:

• non modo = not only
• non ostendit = does not show / does not name

So the structure is not redundant. Each non has a different job:

1. non in non modo helps form the correlative phrase not only
2. non before ostendit negates the verb

English works similarly:

• not only does it not show a co-heir...

There are effectively two negatives there too, but they are doing different things.

Ne ... quidem means not even.

In this sentence:

• sed ne substitutionem quidem continet

This means:

• but it does not even contain a substitution

A very important rule is that the word being emphasized usually goes between ne and quidem.

Here the emphasized word is substitutionem:

• ne substitutionem quidem
• not even a substitution

So the Latin is literally structured like:

• but not even a substitution does it contain

This is a very common idiom, and English speakers should learn it as a unit:

• ne ... quidem = not even

Because ne ... quidem is stronger and more pointed than a simple negation.

Compare the ideas:

• non continet substitutionem = it does not contain a substitution
• ne substitutionem quidem continet = it does not even contain a substitution

The second one adds emphasis. It suggests that the speaker is moving to a more extreme statement.

That fits the logic of non modo ... sed ... very well:

• not only does the will fail in one respect,
• but it does not even include this further provision.

So ne ... quidem sharpens the contrast.

Yes, ostendit is formally ambiguous:

• it can be present active indicative, 3rd singular: he/she/it shows
• or perfect active indicative, 3rd singular: he/she/it showed / has shown

That is a real feature of many Latin third-conjugation verbs.

Here, however, the context strongly suggests present:

• ostendit
• continet

Since continet is clearly present, the parallel structure makes ostendit most naturally present too.

So here we understand:

• the will does not show / name
• not the will did not show

A learner should remember:

• sometimes Latin form alone does not settle tense
• the context and parallelism do

Continet is present active indicative, 3rd person singular, from contineo, continere.

So it means:

• it contains
• it includes

Because the subject is testamentum (the will), the sense is:

• the will contains

There is no ambiguity here like there is with ostendit.

Latin word order is much freer than English word order because Latin uses case endings to show grammatical roles.

English depends heavily on word order:

• the will names a co-heir
• a co-heir names the will These mean different things because the order changes.

In Latin, the endings help show who is subject and who is object, so the writer can arrange words for emphasis.

Here the order highlights contrast and emphasis:

• Testamentum
• non modo coheredem non ostendit
• sed ne substitutionem quidem continet

Some effects of the order:

• coheredem comes before non ostendit, making the missing co-heir prominent
• substitutionem is placed between ne and quidem, which is the normal emphatic pattern for not even
• the whole sentence builds toward the stronger second point

So the word order is not random; it is rhetorically shaped.

Because Classical Latin has no definite or indefinite articles.

So Latin does not normally have separate words for:

• the
• a / an

That means a noun like testamentum can mean, depending on context:

• a will
• the will

Likewise:

• coheredem = a co-heir or the co-heir
• substitutionem = a substitution or the substitution

English must choose one when translating, but Latin often leaves that to context.

Yes. Several words are legal or technical:

• testamentum = a formal will
• coheres = a co-heir
• substitutio = a legal substitution, often the appointment of a substitute heir

So this is not everyday conversational Latin. It sounds like legal discussion or commentary on a will.

That matters for interpretation, because verbs like ostendit may mean not just shows in a general sense, but something more specific like:

• indicates
• names
• designates

In legal Latin, exact wording matters, so a learner should be aware that the sentence may be discussing what is or is not formally stated in a testament.