Past infinitive is a rare grammatical construction in English that combines the infinitive form of a verb with a perfective aspect (e.g., “to have loved” or “to have written”), and in poetry it often conveys retrospection, irrevocability, or existential weight; its use can compress complex temporal relationships into a single phrase, as in T.S. Eliot’s “to have squeezed the universe into a ball,” where the past infinitive encapsulates completed action with lingering consequence, imbuing the present moment with the gravity of what has already transpired yet remains emotionally active.

Past infinitive|device|Infinitive indicating completed action adding narrative richness or retrospective tone. Grammatical poetry tool; usage in storytelling; tip: vary with present forms for temporal layers.