erst als

/eːɐ̯st als/

Erst als is a German temporal conjunction showing that something happens only after a specific event or point in time. Depending on sentence structure, it translates as only when, not until, or only once.

1. only when

The standard neutral translation in past-tense clauses describing a single turning point or threshold event.

Erst als die Sonne unterging, merkten wir, wie lange wir draußen gewesen waren.

Only when the sun set did we realize how long we had been outside.

Er gestand die Wahrheit erst, als die Polizei ihn direkt befragte.

He only told the truth when the police questioned him directly.

Erst als der Arzt die Diagnose bestätigte, glaubte sie es wirklich.

Only when the doctor confirmed the diagnosis did she truly believe it.

2. not until

Emphasizes the delay that must pass before something occurs; slightly more emphatic, and triggers subject-auxiliary inversion when fronted in an English sentence.

Erst als der Vertrag unterschrieben war, konnte das Projekt beginnen.

Not until the contract was signed could the project begin.

Ich verstand seine Absichten erst, als es zu spät war.

I did not understand his intentions until it was too late.

Notes

A key German distinction: erst als is used for unique, completed past events, while erst wenn covers future or habitual situations. This split has no direct parallel in English and often surprises learners. Also note that when not until fronts an English sentence, subject-auxiliary inversion is required: Not until he left did she speak, not Not until he left she spoke.

Synonyms

erst nachdem

Related phrases

erst wenn als sobald kaum dass bis nachdem seitdem