Enough has been said in view of the restricted nature of the evidence, to prove that Mexican religion passed through much the same primitive conditions as other faiths. Further evidence on this point will be adduced as the gods are severally described. We may now proceed to examine such proof as we possess of the onward and upward progress of the cult of rain and growth in Mexico. We may, perhaps, imagine the institution of tribal or village rain or grain fetishes, which in course of time would attain godhead by reason of popularity or supposed auspiciousness. The ministers of these would probably bear a strong resemblance to the medicine-men of North American Indian tribes. Warfare undoubtedly played a great part in the fortunes of these local cults. Thus, did the people of a certain tribal god triumph in feud or battle, his worship would almost certainly be enlarged in a territorial sense. But such a triumph would be a small incentive to further conquest when compared with the absolute necessity for war engendered by the holy law that captives must be obtained for purposes of sacrifice to the tribal deities. THE NECESSITY FOR HUMAN SACRIFICE The origins of the institution of human sacrifice in Mexico are obscure. Native mythology attributed its invention to a group of earth-goddesses headed by Teteo innan or Tlazolteotl, who in the Calendar year “eight-rabbit” came to the city of Tollan or Tula from the Huaxtec country and, summoning the captives whom they had taken in that land, said to them: “We want to couple the earth with you, we want to hold a feast with you, for till now no battle-offerings have been made with men.” [21] This myth is, perhaps, ætiological, but it would seem to have some historical basis. Deeply rooted in the Mexican mind was the idea that unless the gods were abundantly refreshed with human blood they would perish of hunger and old age and would be unable to undertake their hypothetical labours in connection with the growth of the crops. Whence came this idea? Undoubtedly from that process of barbaric reasoning through which Mexican man had convinced himself that the amount of rainfall would be in ratio to the amount of blood shed sacrificially. Seler [22] has indicated his belief in such a process of reasoning by stating that “the one was intended to draw down the other, the blood which was offered was intended to bring down the rain upon the fields.” This, then, is the precise nature of the compact between Mexican man and his gods, Do ut des, “Give us rain, and we shall give you blood.” Once this is understood the basic nature of Mexican religion becomes clear, and all the later additions of theology and priestly invention can be viewed as mere excrescences and ornaments upon the simple architecture of the temple of the rain-cult. THE LATER ELEMENTS OF MEXICAN RELIGION