Past Conditional Verb Tense
A compound tense (like the passé composé or the pluperfect)
Refers to nonexistent conditions and hypothetical outcomes in the past (if X had been true back the, Y would have happened)

Past Conditional (conditionnel) Verb Tense

The conditionnel passé (past conditional)

The French conditional perfect, or past conditional

Verb Tenses
Elements of Grammar