Það kom blettur á gólfið, því málningin datt af penslinum.

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Breakdown of Það kom blettur á gólfið, því málningin datt af penslinum.

• því: because
• gólfið: the floor
• detta: to fall

Questions & Answers about Það kom blettur á gólfið, því málningin datt af penslinum.

Why does the sentence begin with Það if it does not seem to mean it?

Here það is a dummy subject or expletive, much like English there in There appeared a stain on the floor.

So in Það kom blettur á gólfið, það does not refer to a thing. It is just there to fill the first position in the sentence.

A very natural way to understand the structure is:

• Það kom blettur ... = There came / appeared a stain ...
• more idiomatic English: A stain got onto the floor or There was a stain on the floor

This use of það is very common in Icelandic when introducing something new or indefinite.

Why is it kom blettur and not blettur kom?

Icelandic is a verb-second language, which means the finite verb usually comes in the second position of a main clause.

In this sentence:

• Það is in the first position
• kom is therefore in the second position
• blettur comes after the verb

So:

• Það kom blettur á gólfið is structurally very normal

If you said Blettur kom á gólfið, that is possible grammatically, but it sounds more marked and gives blettur more emphasis. The version with það is more natural for introducing a new thing into the discourse.