He begins his references to it in several passages of his Introduction or _Preambulo_, in which he makes some interesting statements as to the use to which the natives put their newly-acquired knowledge of writing, while at the same time they had evidently not forgotten the ancient method of recording ideas invented by their ancestors. The Bishop writes: “The Indians of New Spain retain all the errors of their time of heathenism preserved in certain writings in their own languages, explaining by abbreviated characters and by figures painted in a secret cypher[17-*] the places, provinces and names of their early rulers, the animals, stars and elements which they worshiped, the ceremonies and sacrifices which they observed, and the years, months and days by which they predicted the fortunes of children at birth, and assign them that which they call the Naguals. These writings are known as Repertories or Calendars, and they are also used to discover articles lost or stolen, and to effect cures of diseases. Some have a wheel painted in them, like that of Pythagoras, described by the Venerable Bede; others portray a lake surrounded by the Naguals in the form of various animals. Some of the Nagualist Masters claim as their patron and ruler Cuchulchan, and they possessed a certain formula of prayer to him, written in the Popoluca tongue (which was called Baha in their time of heathenism), and which has been translated into Mexican.[17-†] “Those who are selected to become the masters of these arts are taught from early childhood how to draw and paint these characters, and are obliged to learn by heart the formulas, and the names of the ancient Nagualists, and whatever else is included in these written documents, many of which we have held in our hands, and have heard them explained by such masters whom we had imprisoned for their guilt, and who had afterwards become converted and acknowledged their sins.”[17-‡] The Bishop made up his mind that extreme measures should be taken to eradicate these survivals of the ancient paganism in his diocese, and he therefore promulgated the following order in the year 1692: