Subjonctif imparfait
Summary
The imperfect subjunctive is the literary past of the subjunctive, built on the passé simple stem with -sse endings and a circumflex on the third-person singular; modern French uses the present subjunctive instead.
Explanation
The subjonctif imparfait is the literary past of the subjunctive. It appears in a que-clause under the sequence of tenses: when the main verb is in a past tense (ordonna, craignait) or in a conditional (il aurait fallu), classical usage put the subordinate subjunctive into the imperfect rather than the present. It is the subjunctive counterpart of the imparfait and the passé simple, and like them it belongs essentially to formal, literary writing.
It is formed on the passé simple stem. Take the second-person singular of the passé simple (tu parlas, tu finis, tu fus), add -se, then build the paradigm with -se, -ses, -^t (a circumflex over the vowel in the third-person singular), -ssions, -ssiez, -ssent. Thus parler → que je parlasse, que tu parlasses, qu'il parlât, que nous parlassions, que vous parlassiez, qu'ils parlassent; finir → qu'il finît; être → que je fusse, qu'il fût; avoir → que j'eusse, qu'il eût; venir → qu'il vînt.
The key orthographic point is the third-person singular, which always carries a circumflex on the final stem vowel: qu'il parlât, qu'il finît, qu'il fût, qu'il eût, qu'il vînt. That accent is what distinguishes the subjunctive form from the passé simple indicative: qu'il parlât (subjunctive) versus il parla (passé simple), and especially qu'il fût (subjunctive) versus il fut (passé simple, no accent). Get the circumflex wrong and you have written the wrong mood entirely.
The major pitfall is using it at all in ordinary French: the imperfect subjunctive is effectively obsolete in modern speech and everyday writing, where the présent du subjonctif does its work (qu'il vienne, not qu'il vînt). Its associated compound, the plus-que-parfait du subjonctif (qu'il eût fait), is rarer still. Beyond that, the recurring errors are dropping the circumflex on the third-person singular and confusing qu'il fût with the accent-less passé simple il fut.
Rule of thumb: it is built on the passé simple stem with -sse endings and a circumflex on the third-person singular — but you mainly need to recognise it in classic literature; in real, present-day French use the present subjunctive.
Examples
Il aurait fallu qu'il vînt plus tôt. — He would have had to come earlier. (Conditional main clause (aurait fallu) triggers the imperfect subjunctive; vînt has the circumflex. Modern French: qu'il vienne.)
Elle craignait que nous ne fussions en retard. — She was afraid that we might be late. (Past main verb (craignait) plus the expletive ne; fussions is the imperfect subjunctive of être.)
Le roi ordonna qu'on fermât les portes. — The king ordered that the gates be closed. (fermât shows the third-person-singular circumflex; distinguish it from the passé simple il ferma.)
Je ne croyais pas qu'il eût raison. — I did not think that he was right. (eût is the imperfect subjunctive of avoir, with its obligatory circumflex; not to be confused with eut (passé simple).)
Bien qu'il fût fatigué, il continua. — Although he was tired, he carried on. (qu'il fût (subjunctive, with accent) contrasts with il fut (passé simple, no accent); continua is the passé simple that sets the past frame.)
Common mistakes
Il fallait qu'il finissait son travail.
Il fallait qu'il finît son travail.
After a past main verb like il fallait, classical/literary usage puts the subordinate verb in the subjonctif imparfait, not the indicative imparfait. Finissait is simply the indicative imparfait and cannot follow il fallait que, which requires a subjunctive; in a literary register the correct form is the subjonctif imparfait finît (with its circumflex). In everyday spoken or written French, the sequence-of-tenses rule is relaxed and the present subjunctive is used instead: qu'il finisse.
Prerequisites
Related rules
moodliterarysubordinate-clause