Frater et soror dicunt patrimonium aviae inter duos heredes aeque dividendum esse.

Because the subject is Frater et soror — brother and sister — which is a plural idea. So the verb must also be plural:

• frater = brother
• soror = sister
• dicunt = they say

If there were only one speaker, Latin would use dicit instead.

Aviae is genitive singular, meaning of the grandmother or the grandmother’s.

So:

• patrimonium = inheritance, estate
• patrimonium aviae = the grandmother’s inheritance

This is a very common Latin way to show possession. English often uses ’s, but Latin usually uses the genitive case.

It is accusative because it is the subject of an indirect statement after dicunt.

After verbs of saying, thinking, knowing, perceiving, and similar verbs, Latin often uses the accusative + infinitive construction. In that construction:

• the subject of the reported statement goes into the accusative
• the verb of the reported statement goes into the infinitive

So in this sentence:

• dicunt = they say
• patrimonium ... dividendum esse = that the inheritance must be divided

Even though patrimonium is the logical subject of dividendum esse, it appears in the accusative because of this construction.

This is the Latin indirect statement construction, often called the accusative and infinitive.

Instead of using a word like that plus a finite verb, Latin usually does this:

• main verb of saying/thinking: dicunt
• subject of reported statement in accusative: patrimonium
• infinitive: esse

So literally the structure is something like:

• Brother and sister say the inheritance ... to have to be divided

More natural English is:

• Brother and sister say that the inheritance ... must be divided

Because Latin is expressing necessity here, not just the action of dividing.

• dividere = to divide
• dividi = to be divided
• dividendum esse = to have to be divided / must be divided

This is the passive periphrastic, made from:

• a gerundive: dividendum
• the infinitive esse

It often expresses obligation, necessity, or what ought to be done.

So patrimonium dividendum esse means not merely that the inheritance is being divided, but that it must be divided.

Because it agrees with patrimonium.

• patrimonium is neuter singular
• so the gerundive must also be neuter singular: dividendum

Even though patrimonium is accusative in the indirect statement, the agreement still matches its gender, number, and case:

• patrimonium = neuter singular accusative
• dividendum = neuter singular accusative

So they go together grammatically.

Inter means between or among, and it takes the accusative case.

So:

• inter = between
• duos = two
• heredes = heirs

Therefore:

• inter duos heredes = between the two heirs

A learner may expect something like an ablative, because some Latin prepositions take ablative, but inter specifically takes the accusative.

Because both words must be accusative plural after inter.

• duos is the masculine accusative plural of duo
• heredes here is accusative plural

Since heres is masculine here and refers to heirs, the numeral agrees with it.

So the phrase is fully matched:

• inter duos heredes = among/between two heirs

Aeque means equally.

It tells us how the inheritance must be divided:

• not just divided
• but divided equally

So aeque dividendum esse means must be divided equally.

It is an adverb, so it modifies the verbal idea dividendum esse, not a noun.

Latin does not explicitly say here.

In a passive periphrastic, the person who has the obligation can be expressed by the dative of agent, but that is omitted in this sentence.

For example, Latin could say something like:

• nobis dividendum est = it must be divided by us / we must divide it

But here there is no such dative. So the sentence states the necessity of the action without naming the person responsible.

In context, the people involved might be the heirs, family members, or some legal authority, but the grammar itself leaves that unspecified.

Because Latin usually does not need a separate word like English that in indirect statement.

English says:

• They say that the inheritance must be divided

Latin normally says:

• They say the inheritance to have to be divided

That sounds odd in English, but it is the standard Latin pattern. So after dicunt, the idea of that is built into the accusative-and-infinitive construction rather than expressed by a separate word.

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

This sentence is arranged in a fairly natural and readable way:

• Frater et soror — subject first
• dicunt — main verb
• patrimonium aviae — the thing being discussed
• inter duos heredes — the division phrase
• aeque dividendum esse — the key idea of obligation at the end

Placing dividendum esse near the end gives the sentence a strong finish, since that is the main reported claim: the inheritance must be divided.

Latin could rearrange many of these words and still keep the same basic meaning, though emphasis might change.

With exactly two people, English usually prefers between two heirs.

Latin inter can cover both ideas that English expresses with between and among, but with duos heredes, between is the more natural English choice.

So:

• inter duos heredes = between the two heirs

A useful way to parse it is:

• Frater et soror = subject of the main verb
• dicunt = main verb
• patrimonium = subject of the indirect statement, in accusative
• aviae = genitive modifying patrimonium
• inter duos heredes = prepositional phrase
• aeque = adverb
• dividendum esse = infinitive phrase expressing necessity

So the sentence works as:

• Brother and sister say
• that the grandmother’s inheritance
• must be divided equally
• between the two heirs