Resumptive then (þá)

In Icelandic, when you start a sentence with a conditional ("if") or temporal ("when") clause, it is standard to anchor the following main clause with the resumptive adverb þá (then).

Conditional Clauses with "Ef"

When a sentence begins with ef (if), starting the following main clause with þá firmly establishes the result.

If the storyteller reads the rulebook, then we can start.
Ef sögumaðurinn les reglubókina, þá getum við byrjað.

Because þá occupies the first position of the main clause, it triggers the V2 (verb-second) rule. The verb must come immediately after þá, followed by the subject:

If you step on the trap, then you lose the hit point.
Ef þú stígur á gildruna, þá missir þú lífspunktinn.
If the dice roll is good, then the group defeats the dragon.
Ef teningakastið er gott, þá sigrar hópurinn drekann.

Temporal Clauses with "Þegar"

The same structure applies to time clauses starting with þegar (when). When the þegar clause comes first, the main clause kicks off with þá.

When the character drinks the healing potion, then the pain decreases.
Þegar persónan drekkur lækningadrykkinn, þá minnkar verkurinn.

This pattern works exactly the same way in the past tense:

When the attack began, then the armor was on the table.
Þegar árásin byrjaði, þá var brynjan á borðinu.
When the thief finds the trap, then he uses the magic wand.
Þegar þjófurinn finnur gildruna, þá notar hann töfrasprotann.