Acrisius is the grandfather of Perseus. It was prophesied that Acrisius's daughter, Danae, would have a child that would kill him, and so he locked Danae in a tower to stop her from ever having contact with another man. This failed, as Zeus entered the building in a ray of gold light and impregnated Danae, giving her the child who she named Perseus. Baffled and afraid, Acrisius locked the two of them in a chest and launched them out to sea, but Poseidon (after being asked by Zeus) led the chest to safety on the island of Seriphos, where Perseus grows up.