Pop

Pop is the first of the nineteen periods of the Haab, the 365-day solar calendar of the Maya, which runs alongside the 260-day Tzolk'in. The Haab is built of eighteen months of twenty days each, followed by a short nineteenth period of five days; Pop opens the year. Its name means the mat, the woven reed mat that was a symbol of authority and the seat of a ruler, so the month carried associations of rulership and order. Recorded here by its Yucatec name, Pop, the month is known from the colonial sources and the Classic inscriptions alike. The turning of the year at the seating of Pop was marked by renewal and the refurbishing of household goods. These are the features of the Maya solar calendar, in which every day is named by its position in one of these nineteen periods together with its day in the interlocking sacred count.

Because the Haab has no leap-day correction, its 365-day count, the so-called vague year, drifts against the true 365.2422-day solar year by about one day every four years, so that Pop's seating cycled slowly through the real seasons over the span of a Calendar Round, taking roughly 1,507 years to complete a full circuit back to its original seasonal position. The day on which a year could begin, its Year Bearer, was restricted to one of four of the twenty Tzolk'in day names, spaced five apart because 365 divided by 20 leaves a remainder of 5; the specific set of four differed between the Classic period, when inscriptions show Ik, Manik, Eb and Kaban opening the year, and the Postclassic and colonial Yucatec system Diego de Landa recorded, in which Kan, Muluc, Ix and Kawak served as Year Bearers, a shift epigraphers attribute to a change in counting convention rather than to an error in either system.

One consequence of running a twenty-day month against a twenty-sign day count is easy to miss and worth stating plainly, because it governs the whole shape of a Haab year. Since the Tzolk'in day sign repeats every twenty days and each full Haab month is exactly twenty days long, every month of a given year seats on the same day sign. If a year is seated on Kan, then 0 Pop, 0 Wo, 0 Sip and every other month seating in that year also falls on Kan.

That is why the Year Bearer is a property of the year rather than of the first day alone, and why the same four signs recur in the Postclassic Yucatec sources whenever a year is named: Kan, Muluc, Ix and Kawak. It also means a reader who knows the Year Bearer can work out the day sign of any date in that year from its Haab position alone, without consulting a table.

The pattern survives only within the eighteen full months. The closing Wayeb is five days long, not twenty, so it shifts the alignment by five positions and hands the next year a different bearer, five along in the twenty. Pop, seated first, is where each new alignment is announced.

Two things follow for a reader of dates. First, a Haab position on its own never identifies a year, only a place within one, so an inscription giving a Haab position without a Tzolk'in day is incomplete by design. Second, the Haab count is unbroken: highland Maya communities that kept the 260-day count through five centuries of colonial rule did not keep the Haab in the same continuous way, and its reconstruction rests on the inscriptions and the colonial record rather than on living practice.