I'm reading Kearns(2011) and in Ch9, the author says the sentence "All Torah’s friends were rich then" is ambiguous in the possible scopes of tense and a quantifier NP. I know one meaning is "‘There is a time t earlier than t* such that an event where each of Torah’s friends are rich occurs at t’", but how about the other one? I really can't figure it out.
Perhaps 'then' means something closer to 'in that case' here, ie the speaker could be narrating a situation in the past where some kind of evidence or information has come to light which allowed them to surmise that all of Torah's friends are rich. They say to themself, 'ah, so all Torah's friends are rich then' - in the indirect form of past tense narration this becomes 'All Torah's friends were rich then'.
Not sure if that makes sense in the context, but that's the only other reading which comes to mind for me.