“Leda and the Swan” is a 14-line Petrarchan Sonnet written by William Butler Yeats. It was originally published in The Dial in June, 1924, and was included that year in a collection of poetry by Yeats entitled The Cat and the Moon and Certain Poems. However, Yeats revised the poem several times. Its final version appeared in 1928, in his collection The Tower. The poem is based on a story from Greek myth, in which the Greek god Zeus takes the form of a swan in order to rape the Spartan Queen Leda. This union conceives Helen, whose beauty provokes the Trojan War.

The poem refers to Yeats’s theory of history, which he saw as a series of cycles that move towards violent turning points. The Trojan War represented one such turning point to Yeats. The poem thus uses Leda to explore questions of free will and human agency, depicting her rape as a moment she also possessed the god’s “power” (13) to bring about such historically consequential events. However, the poem doubts that Leda had the omniscience to understand what would follow from that moment.