Wherefore David arose and went, he and his men, and slew of the Philistines two hundred men; and David brought their foreskins, and they gave them in full tale to the king, that he might be the king's son in law. And Saul gave him Michal his daughter to wife. 1 Samuel 18:27

Trivia: Who cut off the end of Saul's skirt while he was going to the bathroom?