When and to whom was the Savior first promised?

Answer:

"So the LORD God said to the serpent: "Because you have done this, you are cursed more than all cattle, and more than every beast of the field; on your belly you shall go, and you shall eat dust All the days of your life. And I will put enmity between you and the woman, and between your seed and her seed; he shall bruise your head, and you shall bruise his heel."" (Genesis 3:14-15).