The allegorical method of interpreting literature was the result of the mediaeval attempt to answer the objections just stated. This method owed its origin to the mode of interpreting the popular mythology first employed by the Sophists and more thoroughly by the later Stoics. Such heroes as Hercules and Theseus, instead of being mere brute conquerors of monsters and giants, were regarded by the Stoic philosophers as symbols of the early sages who had combated the vices and passions of mankind, and they became in the course of time types of pagan saints. The same mode of interpretation was later applied to the stories of the Old Testament by Philo Judaeus, and was first introduced into Occidental Europe by Hilary of Poitiers and Ambrose, Bishop of Milan.[6] Abraham, Adam, Eve, Jacob, became types of various virtues, and the biblical stories were considered as symbolical of the various moral struggles in the soul of man. The first instance of the systematic application of the method to the pagan myths occurs in the _Mythologicon_ of Fulgentius, who probably flourished in the first half of the sixth century; and in his _Virgiliana Continentia_, the _AEneid_ is treated as an image of life, and the travels of AEneas as the symbol of the progress of the human soul, from nature, through wisdom, to final happiness. From this period, the allegorical method became the recognized mode of interpreting literature, whether sacred or profane. Petrarch, in his letter, _De quibusdam fictionibus Virgilij_,[7] treats the _AEneid_ after the manner of Fulgentius; and even at the very end of the Renaissance Tasso interpreted his own romantic epics in the same way. After the acceptance of the method, its application was further complicated. Gregory the Great ascribes three meanings to the Bible,--the literal, the typical or allegorical, and the moral. Still later, a fourth meaning was added; and Dante distinctly claims all four, the literal, the allegorical, the moral or philosophical, and the anagogical or mystical, for his _Divine Comedy_.[8] This method, while perhaps justifying poetry from the standpoint of ethics and divinity, gives it no place as an independent art; thus considered, poetry becomes merely a popularized form of theology. Both Petrarch and Boccaccio regarded allegory as the warp and woof of poetry; but they modified the mediaeval point of view by arguing conversely that theology itself is a form of poetry,--the poetry of God. Both of them insist that the Bible is essentially poetical, and that Christ himself spoke largely in poetical images. This point was so emphasized by Renaissance critics that Berni, in his _Dialogo contra i Poeti_ (1537), condemns the poets for speaking of God as Jupiter and of the saints as Mercury, Hercules, Bacchus, and for even having the audacity to call the prophets and the writers of the Scriptures poets and makers of verses.[9]