Learn Finnish: Luostarissa ei ole ylellisyyttä, vaan vain yksinkertainen elämä. - There is no luxury in the monastery, but rather only a simple life.

In Finnish, negative existential sentences (saying something doesn't exist or isn't in a location) require the subject to be in the partitive case. Since we are saying there is no luxury (ei ole), the word ylellisyys (luxury) becomes the partitive ylellisyyttä.

Why does the sentence use vaan instead of mutta for 'but'?

Vaan is used to mean 'but rather' when you are directly contradicting or correcting a negative statement. Since the first part of the sentence states what is not in the monastery (ei ole), we must use vaan to introduce what is there instead. If the first clause were positive, you would use mutta.

The words vaan and vain are right next to each other. What is the difference?

These two are very easy to mix up! Vaan is a conjunction meaning 'but rather' (used after a negative), while vain is an adverb meaning 'only' or 'just'. Placing them together as vaan vain translates perfectly to 'but rather only'.

Since the sentence starts with the negative ei ole, why is yksinkertainen elämä in the nominative case?