Editing Maya calendar (section)

==Calendar Round==
A Calendar Round date is a date that gives both the Tzolkʼin and Haabʼ. This date will repeat after 52&nbsp;Haabʼ years or 18,980 days, a Calendar Round. For example, the current creation started on 4&nbsp;Ahau 8&nbsp;Kumkʼu. When this date recurs it is known as a Calendar Round completion.

Arithmetically, the duration of the Calendar Round is the [[least common multiple]] of 260 and 365; 18,980 is 73 × 260 Tzolkʼin days and 52 × 365 Haabʼ days.<ref>For further details, see Thompson 1966: 123–124</ref>

Not every possible combination of Tzolkʼin and Haabʼ can occur. For Tzolkʼin days Imix, Kimi, Chuwen and Kibʼ, the Haabʼ day can only be 4, 9, 14 or 19; for Ikʼ, Manikʼ, Ebʼ and Kabʼan, the Haabʼ day can only be 0, 5, 10 or 15; for Akbʼalʼ, Lamat, Bʼen and Etzʼnabʼ, the Haabʼ day can only be 1, 6, 11 or 16; for Kʼan, Muluk, Ix and Kawak, the Haabʼ day can only be 2, 7, 12 or 17; and for Chikchan, Ok, Men and Ajaw, the Haabʼ day can only be 3, 8, 13 or 18.<ref>Kettunen and Helmke (2020), p.&nbsp;51</ref>

===Year Bearer===
A "Year Bearer" is a [[Tzolkʼin]] day name that occurs on 0{{nbsp}}Pop, the first day of the [[Haabʼ]]. Since there are 20 Tzolkʼin day names, 365 days in the Haabʼ, and the remainder of 365 divided by 20 is 5 ({{math|365 {{=}} 18×20 + 5}}), the Tzolkʼin day name for each successive 0{{nbsp}}Pop will be 5 later in the cycle of Tzolk'in day names. Similarly, since there are 13 Tzolk'in day numbers, and the remainder of 365 divided by 13 is 1 ({{math|365 {{=}} 28×13 + 1}}), the Tzolk'in day number for each successive 0{{nbsp}}Pop will be 1 greater than before. As such, the sequence of Tzolk'in dates corresponding to the Haab' date 0{{nbsp}}Pop are as follows:

{{bulleted list
|1 Ikʼ
|2 Manikʼ
|3 Ebʼ
|4 Kabʼan
|5 Ikʼ
|...
|12 Kab'an
|13 Ik'
|1 Manik'
|...
}}

Thus, the Year Bearers are the four Tzolkʼin day names that appear in this sequence: Ik', Manik', Eb', and Kab'an.

"Year Bearer" literally translates a Mayan concept.<ref>Thompson 1966: 124</ref> Its importance resides in two facts. For one, the four years headed by the Year Bearers are named after them and share their characteristics; therefore, they also have their own prognostications and patron deities.<ref>For a thorough treatment of the Year Bearers, see Tedlock 1992: 89–90; 99–104 and Thompson 1966</ref> Moreover, since the Year Bearers are geographically identified with boundary markers or mountains, they help define the local community.<ref>See Coe 1965</ref>

The classic system of Year Bearers described above is found at Tikal and in the [[Dresden Codex]]. During the Late Classic period a different set of Year Bearers was in use in Campeche. In this system, the Year Bearers were the [[Tzolkʼin]] that coincided with 1 Pop. These were Akʼbʼal, Lamat, Bʼen and Edznab. During the Post-Classic period in Yucatán a third system was in use. In this system the Year Bearers were the days that coincided with 2 Pop: Kʼan, Muluc, Ix and Kawak. This system is found in the Chronicle of Oxkutzcab. In addition, just before the Spanish conquest in Mayapan the Maya began to number the days of the Haabʼ from 1 to 20. In this system the Year Bearers are the same as in the 1 Pop – Campeche system. The Classic Year Bearer system is still in use in the Guatemalan highlands<ref>Tedlock 1992: 92</ref> and in Veracruz, Oaxaca and Chiapas, Mexico.<ref name="Miles, Susanna W pp. 273-84">Miles, Susanna W, "An Analysis of the Modern Middle American Calendars: A Study in Conservation." In Acculturation in the Americas. Edited by Sol Tax, pp. 273–84. Chicago: University of Chicago Press, 1952.</ref>