Book of Mani, paragraph 2, “Hun piztun oxlahun ahau,” which Brinton translates “the first year of the thirteenth ahau.” I think the proper translation to be “Tun 1 of Ahau 13,” meaning that 1 tun had passed of Katun 13 Ahau. Paragraph 9, “tu lahun tun uaxac ahau” is translated by Brinton, “and it was the tenth year of the eighth ahau,” while it should be “in Tun 10 of Katun 8 Ahau.” In the Book of Tizimin we find that in Paragraph 1, “tu humpiztun ahoxlahunahau” is translated “to the first year of the thirteenth ahau,” while it should be “to (or in) Tun 1 of Katun 13 Ahau.” Paragraph 11, “Cabil ahau; oxlahun tun” is translated “The second ahau; on the thirteenth, etc.” It should be “on Katun 2 Ahau Tun 13, etc.” Also in the second Book of Chumayel, we find in Paragraph 2, “tu yoxpiztun ychil hun ahau,” which is translated “on the third year in the first ahau,” when it should be “in Tun 3 of Katun 1 Ahau.” Paragraph 3, “Tu uucpiztun uaxac ahau u katunil” is translated “in the seventh year of the eight Ahau katun,” when it should be “in Tun 7 of Katun 8 Ahau.” Paragraph 8, “tu hunpiztun Buluc ahau. Laix u katunil” is translated “in the first year of the eleventh ahau, it was also in this katun,” when it should be “on Tun 1 of Katun 11 Ahau. In this Katun, etc.” Also “tu uucpiztun Buluc ahau u katunil” is translated “in the seventh year of the eleventh ahau katun,” when it should be “in Tun 7 of Katun 11 Ahau.” These two katuns are evidently the same--one date being in Tun 1 and the other in Tun 7 of the same katun--and yet Brinton translated the first as being in the 11th katun and the other as being in the 11th ahau katun. Paragraph 9, “tu uacpiztun ychil ahBolon ahau katun lae.” is translated “in the sixth year of the ninth ahau katun.” It should be “in Tun 6 of Katun 9 Ahau.” Although Brinton has almost always translated “tun” by “year,” it is very evident from the above that the Mayas called the native division of the katun “tun.” It may further be noted that the word “kin” is used for day in the way of numeration in the Book of Mani, paragraph 13, “9 Imix was the day on which Ahpula died” and in paragraph 13 of the Book of Tizimin and paragraph 7 of the first Book of Chumayel, the same statement is made. May it not then be fairly assumed that the Mayas called the day or the unit of their calendrical numeration “kin,” their 360-day period “tun,” and the period of 20 tuns “katun,” as Dr. Seler has suggested?