Ich zaręczyny były w niedzielę.

In Polish, zaręczyny is normally a plural-only noun (pluralia tantum). So even though English says engagement in the singular, Polish treats this idea as plural.

That affects the whole sentence:

• zaręczyny = engagement
• but grammatically it behaves like a plural noun

So Polish says:

• Ich zaręczyny były... = literally Their engagement were..., but naturally translated as Their engagement was...

This is just one of those nouns you need to learn as plural in Polish.

Because the subject zaręczyny is grammatically plural.

The past tense of być (to be) agrees with the subject in number, and in the plural it also reflects grammatical gender category:

• byli = masculine-personal plural
• były = non-masculine-personal plural

Since zaręczyny is not a masculine-personal noun, the correct form is były.

So:

• Ich zaręczyny były w niedzielę.

not:

• Ich zaręczyny była...
• Ich zaręczyny było...

Here ich means their.

It is the Polish third-person plural possessive pronoun:

• ich dom = their house
• ich samochód = their car
• ich zaręczyny = their engagement

A useful thing to know: ich does not change form here. It stays ich regardless of the gender or number of the thing possessed.

No. It is capitalized only because it is the first word of the sentence.

Normally, in the middle of a sentence, it would be written with a lowercase i:

• To były ich zaręczyny.

So this is different from German, where Ich means I. In Polish, ich means their or sometimes them, depending on context.

Because when Polish uses w to mean on with days of the week in this kind of time expression, it usually takes the accusative.

So:

• w niedzielę = on Sunday
• w środę = on Wednesday
• w sobotę = on Saturday

This is a very common pattern for talking about when something happened.

So in the sentence:

• Ich zaręczyny były w niedzielę.
• w niedzielę means on Sunday

It is the accusative singular form of niedziela.

The forms are:

• nominative: niedziela
• accusative: niedzielę

After w in this time expression, Polish uses the accusative:

• w niedzielę = on Sunday

So although w often makes learners think of the locative, here it is part of a set time expression where the accusative is used.

Yes, it is natural and understandable.

Ich zaręczyny były w niedzielę is a simple, correct way to say that their engagement took place on Sunday.

Depending on context, Polish speakers might also say:

• Zaręczyli się w niedzielę. = They got engaged on Sunday.
• Ich zaręczyny odbyły się w niedzielę. = Their engagement took place on Sunday.

The version with były is straightforward and perfectly fine.

The basic order is:

• Ich = their
• zaręczyny = engagement
• były = were/was
• w niedzielę = on Sunday

So literally:

• Their engagement was on Sunday

This word order is neutral and natural.

Because Polish word order is flexible, you could also hear:

• W niedzielę były ich zaręczyny.
• Ich zaręczyny w niedzielę były... (less neutral unless followed by something)

But the original sentence is the most straightforward version.

Polish uses prepositions differently from English.

English says:

• on Sunday

Polish says:

• w niedzielę

So even though w often means in, in this time expression the whole phrase w niedzielę corresponds to English on Sunday.

This is very common in language learning: the preposition itself does not always match word-for-word between languages.

Yes, ich can also mean them, but not in this sentence.

For example:

• Widzę ich. = I see them.

Here, though, ich comes before a noun (zaręczyny) and shows possession, so it means their:

• ich zaręczyny = their engagement

So the function in the sentence tells you the meaning.

Grammatically, były is plural, so if you translated word-for-word, it would look like were.

But in natural English, engagement is singular:

• Their engagement was on Sunday.

So when translating, you follow the normal grammar of the target language, not the literal Polish structure.

This is a good example of how Polish and English organize the same idea differently:

• Polish: plural noun + plural verb
• English: singular noun + singular verb