“And a river went out of Eden to water the garden; and from thence it was parted, and became into four heads” (Gen. ii, 10).[305] These four heads were the sources of the four rivers of Paradise: the Pison, later thought to be either the Indus, the Ganges,[306] or, sometimes, the Danube; the Gihon, or Nile; the Hiddekel, or Tigris; and, finally, the Euphrates. It was a little difficult for some persons at first sight to understand how all these rivers, whose upper reaches were known in reality to be very far apart, could actually spring from one source.[307] Many cosmographers were even tempted to place Paradise in Armenia, near the known sources of the Euphrates and Tigris. In general an appeal to the simple theory of the existence of subterranean watercourses sufficed to solve the problem and to explain the otherwise absurd belief that the Nile had its headwaters in the far east beyond the Red Sea. ASIA _Gog and Magog_ Asia was frequently made the scene of Paradise and of the creation of man. Here, too, medieval tradition placed Gog and Magog,[308] whose advent at the Last Day should bring destruction to the world. There are three different Biblical accounts of Gog and Magog. On the basis of Genesis (x, 2), which makes Magog a son of Japhet, a Jewish tradition conceived of this shadowy and fearful personage as the progenitor of the Scythian tribes. In the book of Ezekiel (xxxviii, xxxix) we read the prophecy of the ravages and destructions of “Gog, the land of Magog, the chief prince of Meshech and Tubal,” who should issue with his terrible hordes from the north and bring death and devastation to the lands of Israel. Finally, in Revelation (xx, 7) we are warned that “when the thousand years shall be finished, Satan shall be loosed out of his prison, and shall go forth and seduce the nations which are over the four quarters of the earth, Gog and Magog, and shall gather them together to battle, whose number is as the sand of the sea.” Here “Gog and Magog” are not the names either of men or of a country, but rather of savage tribes. Most medieval writers, following the Jewish tradition, thought of these tribes as Scythian barbarians of the north—so Josephus, Jerome, and Isidore, though Eusebius believed that they were Kelts, and Jerome referred to a certain history which identified them with the Goths; one chronicle even made the Aquitanians their descendants.[309]