Gustavo Adolfo Bécquer died in Madrid in 1870, thirty-four years old, poor and almost unpublished as a poet. His friends gathered the Rimas and brought them out in 1871, drawn from a manuscript notebook; the order they are numbered in today — this is the fifty-third — is the one those friends gave them. Modern Spanish poetry begins with that small posthumous book.
The poem is built on one promise kept and one broken. Three times it announces that something will return — the swallows to the balcony, the honeysuckle to the garden wall, the ardent words of love to the ear — and three times, in the same breath, it sets aside the only thing that mattered: those swallows that learned our names, those dewdrops we watched tremble, that way of loving. What returns is the kind; what does not return is what was ours.
And it saves the blow for the end. After three stanzas of nature coming back, the last one kneels and tells the whole truth: like this, the way I have loved you — undeceive yourself — no one will love you. It is not a poem about swallows. It is a poem about what does not come again.
The verse is kept in Spanish. Translating it in passing would replace the work with a paraphrase of it.