Why is this 'chegar' and not the past?

[Johan1412]

I don’t understand why it is ‘chegar’ here

Elas tinham partido antes de eu chegar. Why not in the past?

[Joseph]

@Johan1412, “antes de” asks for the infinitive, whether in simple (chegar) or compound form (ter chegado). But the past timeline is established anyway at the start of the sentence. In English, you would have the past tense at the end too (arrived), but Portuguese follows a different logic here.

[Johan1412]

obrigado, Joseph!

[jllsinclair]

I think of it as ‘before arriving’