As for the four tyings located on the tail of each serpent, archaeologists have been in accord in attributing them the value of so many tlalpilli of 13 years, four of which, as everyone knows, formed the classical xiuhtlalpilli, xipoualli, or xiuhmolpilli of the chronological reckonings: 52 years. Each serpent has four tyings, that is to say, 104 solar years are symbolized in the total of the representation. Thus is confirmed the chronological value expressed by the meeting of the heads of the sun and the planet.
We may add that, on the projected part of the cylinder, there are other glyphs, composed in essence of butterflies with stars, groups of flint knives (técpatl), and dots to the number of 156.
We arrive at the important matter of the dates inscribed upon the famous monolith. One only has until today been definitely fixed by archaeologists: the 13-ácatl sculptured within a frame between the tails of the serpents. It is the prominent date of the stone, the one engraved with the most deliberate purpose; its position shows it such.
No one is ignorant that the capital defect of the chronological system of the Indians is that the names of the years repeat themselves every 52 years, each xiuhmollpia. The 13-áacatl (13-canes) of the tablet may be the year 1479, which is the one generally admitted, and 1427 and 1375 and 1323 and 1271 and 1167 and 1115 and 1063 and 699, etc., etc. It is certain that the minute account of Duran, invoked by Don Alfredo Chavero, gives much force to the presumption that the date expresses the year in which the monolith was completed, during Axayacatl’s reign, in 1479. More than that, the stone was in the great temple of Tenochtitlan; it was found in those precincts; there they buried it again between 1551 and 1569, and there later on it was rediscovered, remaining in the base of one of the towers of the basilica until its transference to the site which it now occupies in the museum. There are reasons, then, for believing that it is the stone described by the friar, the consecration of which was the object of so great ceremonies and to which alludes the statement of the natives, therein cited, that it bore “the figure of the sun.” Tezozomoc gives a similar account.Withal, this does not go beyond supposition, and there might be reason for doubt amid the multiplicity of conflicting opinions: that the stone was completed in the time of Chimalpopoca, as Don Antonio Peñafiel believed; in 1352, as Abadiano asserted; in 103 or 231, dates