Breakdown of Não acreditei que a queda do ditador tivesse sido um acidente.
ser
to be
não
not / no
de
of / from / by (means of transport) / wearing (attire)
ter
to have
Questions & Answers about Não acreditei que a queda do ditador tivesse sido um acidente.
Why do we use the Pluperfect Subjunctive (tivesse sido) here instead of the Imperfect Subjunctive (fosse)?
We use the Pluperfect Subjunctive to show that the action in the second part of the sentence (the accident) happened before the action in the first part (your disbelief). While Não acreditei que fosse um acidente means "I didn't believe it was an accident" (viewed as happening around the same time), tivesse sido specifically means it "had been an accident" (an event fully completed before you formed your belief).
How exactly is the Pluperfect Subjunctive formed in tivesse sido?
It is a compound tense formed by using the Imperfect Subjunctive of the auxiliary verb ter—which is tivesse to match the third-person singular subject a queda—followed by the past participle of the main verb ser, which is sido.
What triggers the subjunctive mood in this sentence?
The phrase Não acreditei que (I did not believe that) expresses doubt or denial. In Portuguese, expressing doubt or disbelief in the main clause forces the subjunctive mood in the subordinate clause. If the sentence were affirmative (Acreditei que...), it would represent a perceived certainty, so you would use the indicative mood (tinha sido) instead.
Is the word queda only used for political "falls" like this one?