What did people in the past do about sterility?

I'm thinking, specifically, of high-class nobles and royalty of established civilizations... Now, because the whole concept of marriage, back then, was for the pair to produce children and heirs, what would happen if the wife or husband was sterile? Could it be proven? If divorce wasn't allowed, and if you were a successful buisnessowner with a sterile wife, how would you produce an heir? You'd be totally screwed over, wouldn't you?