The enduring, unsettling resonance of Leda and the Swan

A sudden blow: the great wings beating still

Above the staggering girl, her thighs caressed

By the dark webs, her nape caught in his bill,

He holds her helpless breast upon his breast. 

How can those terrified vague fingers push

The feathered glory from her loosening thighs?

And how can body, laid in that white rush,

But feel the strange heart beating where it lies? 

A shudder in the loins engenders there

The broken wall, the burning roof and tower 

And Agamemnon dead.             

                          Being so caught up,

So mastered by the brute blood of the air,

Did she put on his knowledge with his power 

Before the indifferent beak could let her drop?

-“Leda and the Swan,” William Butler Yeats 

The story of Leda and the Swan has been a motif in Western art ever since Ovid's telling of it some two millennia ago. In the story, Leda, already carrying two children - Castor and Clytemnestra - by her husband, Tyndareus, is raped by the god Zeus, who has taken the form of a swan. She becomes pregnant with Zeus' two children, Polydeuces and Helen (none other than Helen of Troy, over whom a war would be waged and an epic written). 

From the Renaissance on, romanticizing or idealizing portrayals of Leda and the Swan were quite common, the fearsome scene itself often obscured or merely hinted at. But Yeats places the reader at the scene of the crime, evoking a sense of terror that adumbrates the melee of the Trojan War and the death of Agamemnon.