In trīclīniō pater mātrī grātiās agit, quod convīvās benigne accēpit.

Because in can take different cases depending on its meaning.

• in + ablative = in / on a place, showing location
• in + accusative = into / onto a place, showing motion toward

So:

• in trīclīniō = in the dining room (location)
• if it meant into the dining room, Latin would use in trīclīnium

Trīclīnium is a Roman dining room, especially one with dining couches. In many beginner translations it is simply given as dining room.

So in trīclīniō means in the dining room.

Pater is the subject of agit, so it is in the nominative case.

The basic structure is:

• pater = father → subject
• agit = gives / does / offers

So pater ... agit means father ... gives/offers.

Because mātrī is the indirect object: the person to whom the thanks are given.

In Latin, the person receiving something is often put in the dative case.

So here:

• pater = father
• mātrī = to mother
• grātiās agit = gives thanks

Literally, the sentence says something like:

Father gives thanks to mother.

That is why mātrī is dative.

Because grātiās agere is a standard Latin idiom meaning to give thanks or simply to thank.

A very literal breakdown is:

• grātiās = thanks
• agit = he does / drives / gives in this idiomatic expression

But you should learn grātiās agere as a set phrase:

• alicui grātiās agere = to thank someone

So:

• mātrī grātiās agit = he thanks mother

Latin normally uses grātiās in the plural in this expression.

So even though English often just says thanks without thinking about number, Latin idiomatically says:

• grātiās agere = to give thanks

You do not usually replace it with a singular grātiam agit here.

Here quod means because.

Latin quod can have different functions in different sentences, but in this one it introduces a clause giving the reason:

• quod convīvās benigne accēpit
• because she/he kindly received the guests

So it is not a relative pronoun here. It is a conjunction introducing a reason clause.

Accēpit is from accipiō, accipere, accēpī, acceptus, meaning receive, accept, or sometimes welcome depending on context.

The form accēpit is:

• 3rd person singular
• perfect active indicative

So it means:

• he received
• she received
• it received

In this sentence, English will usually translate it as received or welcomed.

Because convīvās is the direct object of accēpit.

The verb accēpit means received/welcomed, and the people being received are the direct object.

So:

• convīvae = guests (nominative plural)
• convīvās = guests (accusative plural)

Here Latin is saying:

• received the guests

That is why convīvās is accusative.

Benigne is an adverb. It describes how the guests were received.

It means things like:

• kindly
• graciously
• pleasantly

So:

• convīvās benigne accēpit = received the guests kindly

Because it modifies the verb, Latin uses the adverb benigne, not an adjective.

The verb accēpit is 3rd person singular, so its subject is understood as he/she/it.

Latin very often leaves subject pronouns unstated when the verb ending already shows the person and number.

So accēpit by itself can mean:

• he received
• she received

In this sentence, the meaning must be worked out from context. Since the sentence says the father is thanking the mother, the intended sense is usually that mother is the one who kindly received the guests.

So Latin does not need to say ea accēpit unless it wants extra emphasis.

Because the sentence describes two actions at different time levels.

• agit = is thanking / thanks → the main action happening now in the story
• accēpit = received / has received → an earlier completed action that explains the reason for the thanks

So the sense is:

Father thanks mother because she received the guests kindly.

In other words, the receiving happened first, and the thanking follows.

Yes, the word order is perfectly normal for Latin. Latin word order is much freer than English word order because the case endings show the grammatical roles.

English depends heavily on position:

• Father thanks mother is different from Mother thanks father

Latin can be freer because:

• pater is nominative, so it is the subject
• mātrī is dative, so it is the indirect object
• convīvās is accusative, so it is the direct object

So even if the order changes, the endings still show who is doing what.

This sentence begins with in trīclīniō to set the scene first: in the dining room.

Not naturally in this sentence. Here quod gives the reason, so because is the right translation.

A translation with that would sound wrong in English:

• Father thanks mother, that she received the guests kindly ✗

So in this sentence, think of quod as a conjunction of cause:

• because

Classical Latin has no articles like English the or a/an.

So words like:

• pater can mean father, the father, or sometimes a father
• mātrī can mean to mother or to the mother
• convīvās can mean guests or the guests

The exact English wording depends on context. In a sentence like this, English usually adds the where it sounds natural:

• In the dining room, father thanks mother because she kindly received the guests.