Zeus’s wife and sister, Hera, was responsible for marriage, fertility, and childbirth. She was best known for her angry reaction to her husband’s infidelities, and the targets of her sometimes violent retributions were more often Zeus’s victims than Zeus himself. When Zeus had relations with Hera’s priestess, Princess Io of Argos, he tried to protect her from Hera’s wrath by disguising her as a beautiful white cow. Hera saw through the trick and sent a gadfly to chase the poor cow around the world. Io crossed the sea, which was later named the Ionian Sea after her. She also crossed the straits between Europe and Asia, causing them to be named the Bosphorus (Cow’s Crossing).