Ubi primi convivae venerint, serva eis pocula pura offeret.

Here it means when (or as soon as), not where.

Latin ubi can be:

• interrogative/relative of place: where
• temporal conjunction: when

In this sentence, it introduces a time clause:

• Ubi primi convivae venerint = When the first guests have arrived

So the idea is temporal, not locational.

Venerint is the 3rd person plural future perfect active indicative of venire.

So literally it means:

• they will have come
• more naturally in English here: they have arrived / arrive

Latin often uses the future perfect in a subordinate time clause when one future action must be completed before another future action happens.

So the sequence is:

• first: the guests arrive
• then: the maid will offer the cups

That is why Latin uses:

• venerint = will have arrived
• offeret = will offer

In form, yes: venerint can look like either

• future perfect indicative, or
• perfect subjunctive

But in this sentence, it is understood as future perfect indicative.

Why? Because:

• ubi introduces a temporal clause
• the main verb is future: offeret
• the sense is straightforward future time: when the first guests have arrived, the maid will offer...

That combination strongly points to the future perfect indicative, not the subjunctive.

Primi convivae is nominative plural.

It is the subject of venerint:

• convivae = guests
• primi = first

So:

• convivae is the noun
• primi is the adjective agreeing with it in case, number, and gender

Together they mean the first guests.

Because conviva is one of those Latin nouns in -a that is not necessarily feminine.

English speakers often learn:

• first declension = usually feminine

That is a good rule of thumb, but not an absolute rule.

Conviva, -ae is a first-declension noun meaning guest or table-companion, and it can refer to a man or a woman depending on context. So its first-declension ending does not mean it must be feminine.

Because Latin does not have a definite article like English the.

So Latin often leaves definiteness to context.

For example:

• primi convivae can mean the first guests
• serva can mean the maidservant or a maidservant
• pocula pura can mean the pure/clean cups or just pure/clean cups

English usually has to choose the or a, but Latin does not mark that distinction in the same way.

Here it is a noun, meaning maidservant or slave-girl.

Grammatically it is nominative singular, and it is the subject of offeret:

• serva ... offeret = the maid will offer

A learner may notice that serva could also look like an imperative form of servare in isolation, but that is not what is happening here. In this sentence, syntax makes it clear that serva is the subject noun.

Eis is dative plural of is, ea, id, and here it means to them.

It is the indirect object of offeret.

With a verb like offerre (to offer), Latin often has:

• the thing being offered = direct object
• the person receiving it = indirect object in the dative

So in this sentence:

• eis = to them
• pocula pura = the pure/clean cups (or drinks, depending on context)

Pocula pura is accusative plural neuter.

• pocula is the accusative plural of poculum
• pura is an adjective agreeing with it

So both words are:

• accusative
• plural
• neuter

The ending -a on pura may look feminine to an English-speaking beginner, but here it is neuter plural, not feminine singular.

This is a very common pattern in Latin:

• neuter plural nominative/accusative often ends in -a

So:

• pocula pura = pure/clean cups (or pure drinks, depending on context)

Offeret is 3rd person singular future active indicative of offerre.

So it means:

• he/she/it will offer

Here the subject is serva, so:

• serva ... offeret = the maid will offer

This matches the future-time setting of the whole sentence:

• when the guests have arrived,
• the maid will offer...

Because Latin word order is much more flexible than English word order.

English relies heavily on position:

• subject → verb → object

Latin relies much more on endings to show each word’s job in the sentence.

So Latin can arrange words for:

• emphasis
• rhythm
• style
• clarity

In this sentence:

• the time clause comes first: Ubi primi convivae venerint
• then the main clause: serva eis pocula pura offeret

That is very natural Latin.

A very literal word-for-word order would be something like:

• When the first guests have arrived, the maid to them pure cups will offer

But good English rearranges it:

• When the first guests have arrived, the maid will offer them pure/clean cups

So the unusual order is not strange Latin; it is just Latin using its normal flexibility.