Returning to the same word, the same sentence or the same construction, at the start of successive verses or sentences (anaphora) or throughout the text, to give rhythm, emphasis or insistence.
In Purgatory
but Virgil had left us deprived of himself, Virgil sweet father, Virgil to whom I gave myself for my salvation.
The name "Virgil" opens three times in a row, each time with a new title: "sweet father" and "to whom I gave myself." The repetition grows like a call without an answer and measures the loss by the affection that each return accumulates.
Cantos XXX to XXXIII: Beatrice, Dante, narrator, on discovering that Virgil has vanished