Who is Saul from A Tale of Three Kings and what is their importance?

Saul is the mad king with whom David goes to live. Saul is a decent king, but when David comes to live with him he begins to believe that David is after his kingdom. Saul becomes full of jealousy. Saul begins to harm David by throwing spears at him. Saul wants to stop David from becoming the good man that he can see he is going to be. However, David fails to allow Saul's cruel behavior to upset him. David allows the spears to fall away and he does not throw any of his own spears. This further annoys Saul who decides he wants David to be murdered. Saul sends men to kill David. When David learns this, he leaves Saul's kingdom. In doing so, David is followed by other people who have suffered under the mad king and thus becomes a king in his own right.