The monotheistic or dualistic nature of the faith as originally taught by Zoroaster has, in the later religious writings and practices, been overlaid and obscured by the different phases of nature worship. Fire is accepted as the symbol of holiness, but, according to the views of the educated Parsees, is not itself the thing worshipped. The existing canon of the _Avesta_ was compiled and published under the direction of King Sapor II., who reigned 309-330 A.D. Among the poems of the _Avesta_ we find the legend of which the hero is Rustem, who stands as the representative of Iran in its long contest with Turan. The literature of Persia prior to the fourth century of the Christian era was probably controlled in great part by the priests. The exceptions would have been in the case of the court poets or court historians, writing under the incentive of royal remuneration. It is probable that songs and recitations were to some extent given to the public by minstrels or rhapsodists. There is some evidence also of the development in later centuries of the story-teller or improvisatore, who made a business of exchanging, for the pence of the public, stories partly original, but chiefly borrowed from older sources. The Oriental capacity for story-telling, and the Oriental readiness to devote an abundance of leisure time to listening to stories, is clearly indicated not only by modern practices, but also by the history of such collections as the _Arabian Nights_. Of this famous series of tales, neither the nationality nor the date of origin has been fixed with any degree of certainty. It is probable, however, that the collection first took shape in Bagdad about 1450 A.D., the date of the invention of printing. Von Hammer is of opinion that the Bagdad Tales are based upon a Persian collection called _Hezar Afsaneh, The Thousand Fanciful Stories_. From a passage in the _Golden Meadows_ of El-Mesoudee (quoted by von Hammer) this Persian collection is known to have been in existence as early as 987 A.D. It seems probable, as suggested, that the practice of publicly reciting poems or of narrating stories prevailed in Persia from a very early date, and constituted here, as in Greece, the first method for the distribution or the publication of literary compositions. The material employed for manuscripts was first _diphtherai_, or skins, and later papyrus and parchment.