We are compelled to suppose that in the case of all the Gods of this nature the idea of the dying away of vegetation during the heat of the year and its revival had become intertwined and commingled with that of the declining and reviving strength of the sun. Thus, from this mingling of two distinct lines of thought, we have to explain the variations of the double-natured character of the Sun-Gods and Vegetation-Gods of Western Asia. [149] It is obvious, however, that the sun can only be regarded from such a tragic standpoint in a land where, and in the myths of a people for whom, it possesses in reality such a decisive significance that there are grounds for lamenting its absence or lack of strength during winter and for an anxious expectation of its return and revival. [150] But it is chiefly in the highlands of Iran and the mountainous hinterland of Asia Minor that this is the case to such an extent as to make this idea one of the central points of religious belief. Even here it points back to a past time when the people concerned still had their dwelling-place along with the kindred Aryan tribes in a much more northerly locality. [151] Thus Mithras, the "Sol invictus" of the Romans, struggling victoriously through night and darkness, is a Sun hero, who must have found his way into Persia from the north. This is shown, amongst other things, by his birthday being celebrated on the 25th of December, the day of the winter solstice. Again, the birth of the infant Dionysus, who was so closely related to the season Gods of Nearer Asia, used to be celebrated as the feast of the new birth of the sun at about the same time, the God being then honoured as Liknites, as "the infant in the cradle" (the winnowing-fan). The Egyptians celebrated the birth of Osiris on the 6th of January, on which occasion the priests produced the figure of an infant from the sanctuary, and showed it to the people as a picture of the new-born God. [152] That the Phrygian Attis came thither with the Aryans who made their way from Thrace into Asia Minor, and must have had his home originally in Northern Europe, appears at once from the striking resemblance of the myth concerning him with that of the northern myth of Balder. There can be no doubt that the story in Herodotus of Atys, son of Croesus, who while out boar hunting accidently met his death from the spear of his friend, only gives another version of the Attis myth. This story, however, so closely resembles that of the death of Balder, given in the Edda, that the theory of a connection between them is inevitably forced upon one's mind. In the Edda the wife of Balder is called Nanna. But Nanna (i.e., "mother") was according to Arnobius [153] the name of the mother of the Phrygian Attis.