Acrisius, king of Argos, had only one child, a daughter. When consulting an oracle hoping for a future son by his queen, he was told it would be not his son, but his grandson who will inherit the kingdom- after killing him. Acrisius returned home troubled and made plans to keep his daughter a virgin by locking her up in a bronze tower safe-guarded by savage dogs. Unfortunately for Acrisius, Zeus saw Danae and visited her in the form of golden rain and impregnated her.