Hypothetical Past Conditions
In a previous lesson, you learned how to express simple "if" statements concisely using de + infinitive. To talk about hypothetical situations in the past—imagining how historical decisions might have played out differently—you can use de with the compound infinitive.
To form this, use de haber followed by the past participle of your action verb. This translates to "If [someone] had [done something]".
| If she had foreseen the defeat, the queen would have retreated. | De haber previsto la derrota, la reina se habría retirado. |
When your "if" condition has an explicit subject (like el aliado or la invasión), it generally comes immediately after the past participle.
| If the ally had intervened, the invasion would have failed. | De haber intervenido el aliado, la invasión habría fracasado. |
| If the invasion had failed, the ally would have tried it again. | De haber fracasado la invasión, el aliado habría vuelto a intentarlo. |
Pronouns with Compound Infinitives
When you use reflexive verbs or object pronouns in this structure, attach the pronoun directly to the end of haber, creating words like haberse or habernos. The past participle itself remains unchanged.
| If they had retreated before, the victory would have been impossible. | De haberse retirado antes, la victoria habría sido imposible. |
The Result Clause
The second half of these sentences usually describes what would have happened. To do this, use the conditional perfect (habría + past participle).
| If she had intervened, the empress wouldn't have lost the throne. | De haber intervenido, la emperatriz no habría perdido el trono. |
However, if you are describing how an alternative past event would affect the present, you can simply use the conditional tense (like sería or estaría) in the result clause instead.
| I saw the defeat; if we had triumphed, everything would be different. | Yo vi la derrota; de haber triunfado nosotros, todo sería distinto. |