The _Iter ad Paradisum_ and the various versions of the legend of St. Brandan’s voyage are examples of a type of story very common in the Middle Ages, the story of actual journeys to Paradise by mortal men.[1222] Among these we should include the account of the visit there of Adam’s son, Seth, who brought back seeds from the tree of knowledge which were planted in Adam’s mouth after the latter’s death; the seeds ultimately sprouted into a great tree, the wood of which was used to make Christ’s cross.[1223] Tales were told of the sojourns of pious monks in Paradise and of how on their return to the homes of men they found that what had seemed only three days in the Garden of Delights was in reality a period of three hundred years. Godfrey of Viterbo in his _Pantheon_[1224] relates a tale of a hundred brothers who, like St. Brandan, made widespread explorations in the ocean before coming to Paradise, a golden mountain redolent with wonderful odors and adorned with an image of the Virgin and Child. Another story, dating from an earlier time but undoubtedly well known during our period, was that of the fabulous St. Macarius.[1225] Three brothers from a convent between the Tigris and Euphrates set out to find the place where “the earth joins the sky.” After crossing Persia they entered India—a land of wonders, of cynocephali and of pygmies, of serpents and of darkness. Here they came upon the altars set up by Alexander the Great to mark the limits of his wanderings,[1226] and beyond them reached miraculous countries filled with giants and birds that talked. At last, about twenty miles from the Terrestrial Paradise, they found Macarius, a man of hoary age, dwelling in a cave on friendly terms with two lions. Macarius told them a romantic story, in the course of which he described the wonders of Paradise but, alas, emphasized the fact that this long-sought-for garden was absolutely inaccessible to human beings. THE RIVERS OF PARADISE The account of the four rivers of Paradise, like other passages in Scripture, was interpreted both allegorically and literally. In the religious art of our period these streams were often depicted in stone, glass, or miniature as symbolizing the four evangelists spreading the gospel throughout the world.[1227] Neckam, after mentioning Paradise and the rivers, goes on to explain that, just as the world is watered by the four streams, so “by the gift of the Holy Ghost the garden of the Holy Church is irrigated by the four virtues, Justice, Temperance, Fortitude, and Prudence.”[1228] Literal interpretation of the passage, on the other hand, would present difficulties to the modern hydrographer, but these difficulties were easily overcome in the Middle Ages by appeal to the familiar theory of subterranean watercourses.[1229]