Again, after the Mexicans had been settled at Tenochtitlan for some time, they desired to make an alliance with the King of Culhuacan and therefore “chose to nominate, as their ruler, Acamapichtli, who was the son of a Mexican chieftain by a daughter of the Culhuacan ruler” and evidently lived with the latter. For it is related that, on giving his consent, the king of Culhuacan stated that if only a _woman_ (of his family) had been nominated he would have refused (to trust her to the Mexicans). The farewell words he addressed to Acamapichtli are worthy of quotation: “Go my son, serve thy god, be his representative. Rule the creatures of the god by whom we live; the god of day, of the night and of the winds. Go and be the lord of the water and land owned by the Mexicans.” As it is subsequently stated that Acamapichtli _and his queen_ were received at Tenochtitlan with great honors, it would seem as though the Mexicans who, from some deeply-rooted religious idea, considered it essential to have a female ruler of the line of the king of Culhuacan, obtained their desire only by accepting a male member of her family as a protection and safeguard for her sacred person. It may be that for the reasons of safety and preservation the female ruler, who was the living representative of the Cihuacoatl, gradually retired into absolute seclusion whilst a man of her kin assumed, in public, her title and prerogatives. Unless it is assumed that this was the case, it seems impossible to explain why Acamapichtli is designated in the Codex Mendoza (Kingsborough, vol. I, pl. II) as having begun to rule in the year I Tecpatl or flint (approximately corresponding to A.D. 1364) with the title of “Woman-serpent”=Cihuacoatl. From this date the title seems always to have been borne by a man. When human sacrifices had become a prominent feature of the native cult and it became a duty of the Cihuacoatl to perform the bloody rite, it is obvious that it became impossible for a woman to fill the position.