Iwein is an early 13th century, Middle High German work in rhymed verse. It was in all probability written by a ministerialis who worked for one of the nobility. The author claimed to be a knight who also read whatever he could find. He lived during an era in which it was unusual for knights to be literate.

In Iwein, probably Hartmann's last work, the eponymous hero learns of a fountain with magical powers. When Iwein pours water on the stone there, a fearful storm unleashes its violence against him and the trees. The animals and birds flee. The protector of the fountain appears, challenging him to a joust. Iwein succeeds in defeating this individual, but becomes trapped inside the castle to which his enemy has fled. There, Iwein is rescued by a maiden, who convinces her mistress, the queen Laudine, to marry the knight who has felled her husband. The maiden, Lunete, produces Iwein and he and the queen marry.

After their marriage, the famous Gawein convinces Iwein to go away with him for a year to fight in tournaments. Laudine warns Iwein that, if he does not return within one year, she would reject him forever. Iwein protests that one year would be much too long for him to stay away, but the urging of his friend, Gawein, proves too much for him, and Iwein stays away too long.

When Laudine sends a messenger, the maiden Lunete, to inform Iwein of her rejection and demand the return of her ring, Iwein goes insane. After a long period, another maiden delivers Iwein from his ravings by means of a magic salve. At first, Iwein believes he has only dreamed of his former life as a knight, but finally realizes that his defeat of the knight of the fountain, his marriage to Laudine, and his subsequent loss are all true. He must find a way back into Laudine's heart and rescue the hapless Lunete, whom the queen has sentenced to death for advising her to marry Iwein. ( )