There are two principal points in the Indo-Īrānian religion. First, that there is a law in nature; and second, that there is also war in nature. There is law in nature, because day returns with its golden splendor and night with its eloquent mystery; seed-time and harvest, the planting and the fruiting, succeed each other with unfailing regularity. There is war in nature, because it contains powers that work for evil, as well as those that work for good. Hence the unceasing struggle goes on, and it is never more apparent to the human eye than in a storm, where a fiend seems to bear away the waters which the earth so sadly needs, and fights with the god who at last brings them to the thirsting plants. Amidst all the various myths of the Indo-Īrānian system there is a monotheism and an unconscious dualism. But both of these disappeared in the further development of Hindū mythology. Mazdeism, however, lost neither of these two ideas; it clung strongly to them both. Hence we have the Ahūra-Mazda, “the lord of high knowledge,” “the all- embracing sky.” He was the Varuṇa of the Hindūs, but this name was lost in Īrān, or remained only as the name of a mythical region—the Varena, which was the scene of a mythical fight between a storm-fiend and a storm-god. Ahūra, the heaven-god, is white, and his body is the fairest and greatest of bodies. He is wedded to the rivers, and the sun is his eye, while the lightnings are his children, and he wears the heavens as a star-spangled garment. In the time of Herodotus, the Persians, while invoking Ahūra-Mazda as the creator of heaven and earth, still called the whole vault of the sky the supreme god. This deity slowly brought everything under his sway, and the other gods finally became, not only his subjects, but also his creatures. While the single elements of Mazdeism do not differ essentially from those of the Vedic and the Indo-European mythology generally, still the grouping of these elements in a new order presents them in a new form. Thus we find that in Mazdeism everything is referred either to Ahūra Mazda or to Angra Mainyu as its source, and hence the world is divided into two parts, in each of which a strong unity prevails, representing the dualism of this system. Ahūra is all light, truth, goodness and knowledge, while Angra Mainyu, or Ahriman, is all darkness, falsehood, wickedness and ignorance. Man, according to his deeds, belongs to Ormazd or to Ahriman. He belongs to Ormazd if he sacrifices to him, and helps him by good thoughts, words and deeds; if he enlarges his dominion and makes the realm of Ahriman smaller by destroying his creatures; while the man who is a friend of Ahriman and represents evil thoughts and evil deeds, who slays the creatures of Ormazd, is classed as a demon. Even animals are classified as belonging to one spirit or the other, in accordance with the idea that they had been incarnations of either the god or the fiend.