Who else but Zeus? Leda was beautiful and—looking down on Sparta that afternoon—the sight of her lying naked on a riverbank had been more than he had been able to resist. In order to have his way with beautiful girls, boys, nymphs, and sprites of one kind or another, the King of the Gods had transformed himself in many extraordinary ways over the course of a long lustful career. Eagles, bears, goats, lizards, bulls, boars—even a shower of golden rain in one case. A swan seems almost routine by comparison.