The traditional tales and stories of ancient Iran describe confrontations between good and evil, the victories of the gods and the exploits of heroes and fabulous supernatural creatures such as the magical bird Simurgh and the "div" or demons. Much information about Iran"s pre-Islamic past comes from the holy book of the Zoroastrian religion, the "Avesta", which was not written down in its present form until the 13th or 14th century but parts of it date back originally to between 1400 and 1200 BC. As well as the words of the prophet Zoroaster, and stories about the Wise Lord Ahura Mazda, it incorporates earlier pagan myths which reappear in the "Shahnameh" (Book of Kings), an epic in rhyme completed in AD 1010 by the poet Firdowski and featuring his most famous hero, Rustan.