The Stone of the Sun and the First Chapter of the History of Mexico/Name and position of the monolith
As concerns the name of the stone, considering that it is the sum total of the chronological system of the aborigines, founded in mathematically defined cycles, none is more exact than that proposed by Don Alfredo Chavero, the “Mexican Cyclographic Stone”; but we believe that it will not be possible to displace the designation “Aztec Calendar,” imposed by the first eminent interpreter of the monument, and by which it is universally known. Strictly it is a calendar, in the elevated and broad sense, since it contains the measure of time; but we cannot absolutely assert or deny that it is Aztec work. The name "Stone of the Sun" fits without doubt, though only partially since it is really "Stone of the Sun and of Venus."
Concerning the position in which the Aztecs maintained it, we cannot bring ourselves to admit that it was placed horizontally. Incredible and even absurd to sculpture, with infinite art and labor, such marvelous works that they should remain almost concealed! Nevertheless, Seler, following Chavero in this as in some other points, holds that the purpose of the stone was the practicing of sacrifices upon it, attempting to identify it with a si mple cuauhxicalli, which had wrought upon it the face of the sun and the signs of the days. It is well understood that this stone was something of much less importance that the relief of the museum, synthesis of the history of the world and of the science of the aborigines. Much less can we admit, as Mrs. Nuttall claims in her erudite study (Key-Notes of Ancient American Civilizations) that it was placed in the ceiling of a building with relief downward, in such a position that certain of the symbols were to the east; the thesis is so strange that we will not discuss it.
No, the central Tonatiuh, in the height of the zenith, with the claws opened, magnificently suspended in space, eloquently proclaims how the natives placed the monument. In the imagination of those men, the sun, when he crosses the firmament suggested an eagle cleaving space in his powerful flight; and, in fact, the star of day and the eagle appear intimately associated in the codices. They called the sun Quauhtleuatl or Quauhtleoauitl, "The Eagle That Ascends." On the other hand, the dates inscribed below the arrow, giving them the meaning ascribed to them by Gama and Chavero, result without sense under the preceding unacceptable theses. The sufficiently probably theory that the stone was used in the mode of a solar timepiece, by means of gnomons, the sockets for which are clearly preserved, also falls to the ground. Lastly, how could the point of the arrow indicate the meridian of Mexico, if the monolith were in a horizontal position?
It is necessary to convince one's self of this: the relief was placed vertically in the great teocalli, as we see it today, although with its face to the south and oriented exactly with reference to the east and west. If this stone is the one described by Durán, we must supposed that they laid it down in order to make sacrifices upon it; but, the cruel ceremony ended and innumerable victims sacrificed to the god of blood, they would again erect it in the only position admissible, that in which the Indians could contemplate the face of their deity and read the Teoamoxtli, the marvelous page written on the surface of the relief; the history of the world divided into periods of 416 years, formed by the continuous gyration of the 20 days of the month, of the 260 days of the tonalámatl, of the 365 days of the civil year, of the 2,920 of the Venus period, of the 18,980 of the sacred cycle in which they adjusted the tying, of the 37,960 of the greater cycle in which the movements of the sun and star combine, and of the 151,840 of the great era in which all teh elements of the chronology harmoniously adjust their admirable mechanism. And as religion and time measurement formed with the observation of the heavens one single body of ideas, the stone came to be actually the sum total of the mythologico-astronomical conceptions of the natives.
In the cycle of 52 years the elements of the solar calendar closed their round, in order to repeat themselves in the following period: this was the famous festival of the making of the new fire, of which all the histories speak. The cycle of 104 years, adjustment of the calendars of the sun and Venus, was much less celebrated, because of its long duration; the citation from Sahagún and the hieroglyphs of codices and monuments demonstrate, nevertheless, that the Indians considered it also, certainly with extraordinary solemnity. Lastly, the great period of 416 years, of extreme amplitude, was rather a calculation of mathematicians, a theoretical rather than practical arrangement; nevertheless, the occasion for its celebration presented itself once during the history of the Aztecs: when the people of Tenoch counted 416 years from the time of their exodus from Aztlan. It occurred in 1479. The unusual importance of the anniversary explains the construction of so grandiose a monument: they desired to stamp thereon, succeeding admirably, the fundamental ideas of their culture and the supreme dates in their past. The great stone of the museum, Cyclographic Stone of the pre-Columbian civilizations of America, is certainly the stone of the history of the world, according to the cosmogony and beliefs of the Indians, and in particular of the history of the constructing race up to the moment when the monolith was erected. We know of no people which has raised another more admirable and marvelous. 
GREAT CHRONOLOGICAL CYCLE OF
416 YEARS. MAUSOLEUM NO. III
OF CHICHEN ITZA