Vis and Ramin
A Parthian noblewoman
King Mobad of Marv saw the beautiful Queen Shahru, and asked her to marry him, but she was already married. Instead, Queen Shahru promised to send King Mobad her daughter to marry, if she had one. So when her baby Vis was born, Queen Shahru sent Vis to the court of King Mobad, and Vis grew up there with Mobad's younger brother Ramin, who was about the same age. When Vis was a teenager, they sent her back to her mother to get ready to be married.
But when Vis got home, Queen Shahru had forgotten her promise, and she made Vis marry her own brother, Viru, instead. When King Mobad's sons found out, there was a battle, and Vis' father the king was killed. Vis reluctantly agreed to go with Ramin, who would take her to King Mobad to be married to him, but on the way there, Ramin fell in love with her, and with some help from her nurse, Vis fell in love with him too.
When King Mobad found out that Vis and Ramin were in love, he ordered Vis to pass a test to prove that she was faithful to him: she would have to walk through fire, and if the fire burned her, that would show she had been unfaithful. But instead, Ramin and Vis ran away together. Finally King Mobad and Ramin's mother made peace, and Ramin and Vis came back to the city of Merv, and Vis married King Mobad.
King Mobad and Ramin went off together to fight the Romans. When Ramin was wounded, he went home and got together with Vis again. But when King Mobad got home, Ramin had to run away again. Now Ramin gave up on Vis and married another woman, Gol. Vis begged Ramin to come back, and finally they did get back together again. The story has a happy ending when King Mobad was killed hunting boar, and his younger brother Ramin became the king, with Vis as his wife, and they lived happily ever after.
The City of Rainbows: A Tale from Ancient Sumer, by Karen Foster (1999). For kids, a great story from the University of Pennsylvania Museum. Two kings fight, and Ishtar settles it.
Gilgamesh the King, The Revenge of Ishtar, and The Last Quest of Gilgamesh by Ludmilla Zeman (1998-9). This is a set of three kids' books that retell the story of the Epic of Gilgamesh in an age-appropriate way. Lovely pictures.
For information about the invention of writing and the alphabet, check these out:
The Invention of Cuneiform: Writing in Sumer, by Jean-Jacques Glassner, Marc Van De Mieroop, and Zainab Bahrani (2003).
Language Visible : Unraveling the Mystery of the Alphabet from A to Z, by David Sacks (2003). The history of the invention of our own alphabet.