Andrew Lang 
The Red Fairy Book 

ONCE upon a time there was a King in the North who had won many wars, but now he was old. Yet he took a new wife, and then another Prince, who wanted to have married her, came up against him with a great army. The old King went out and fought bravely, but at last his sword broke, and he was wounded and his men fled. But in the night, when the battle was over, his young wife came out and searched for him among the slain, and at last she found him, and asked whether he might be healed. But he said 'No, ’ his luck was gone, his sword was broken, and he must die. And he told her that she would have a son, and that son would be a great warrior, and would avenge him on the other King, his enemy. And he bade her keep the broken pieces of the sword, to make a new sword for his son, and that blade should be called Gram.