Simplify the following text for a Grade 8 native English-speaking person.
Original: The nucleus of these stories is formed by an old Persian book called Hezar-afsana or the `` Thousand Myths '' ( Persian : Ù Ø Ø Ø Ø Ù Ø Ø Ù Ù ) .
Simplified: The main part of these stories is formed by an old Persian book called Hezar-afsana or the `` Thousand Myths '' ( Persian : Ù Ø Ø Ø Ø Ù Ø Ø Ù Ù ) .