The Haab
The Haab is the cycle of the calendar the Maya use for recording the year. From a contemporary point of view, it has some very unusual properties. Instead of dividing the months into twelve sections, it divides the year into eighteen sections of twenty days each. Each of these periods is called a uinal and has a special glyph and name. The days of the uinal are numbered from zero to nineteen. For example, the uinal of Pop starts on the day 0 Pop, also known as the seating of Pop, and finishes on the day 19 Pop.
This gives a total of 360 days, which is a nice round divisible number but somewhat short of the true length of the year, which lasts 365.2422 days. The Maya compensated for this by adding five extra days at the end of the year called the Uayeb. These were considered unlucky days, when the gods rested and the normal barriers between the underworld and the waking world were open because the days fell outside the round of the year.
Rites of purification, fasting, and prayer marked the time. The beginning of the next year was waited for expectantly.
The division of the year into 360 days plus an additional five is not unusual. The ancient Egyptian calendar did the same thing and also had a period at the end of the year when the gods rested. There are Jewish, Chinese, and Indian calendars that also use 360-day cycles. It seems that the desire to make the year into an orderly and exact cycle has been a long and persistent tradition.
The Maya did not make any provision for the remaining quarter day of the year and they recorded no leap year. As a consequence of this, the beginning of the year drifted through the conventional year over time. At the time of the European invasion, the beginning of the Haab, on the day 0 Pop, was equivalent to the date July 26 in the Julian calendar. Over the passing centuries, this has drifted backward, to the end of February.
This kind of arrangement would be pretty unthinkable to most of us. Certainly it made the Haab somewhat ineffective as an agricultural calendar. For a while, archaeologists thought that the Maya just weren't able to work out the length of the year. This isn't the case though, as it has been shown that some inscriptions actually record corrections for this backward drift. The reality is that they didn't really care too much about it. Instead, they were interested in making sure that a bigger cycle called the calendar round tied up accurately; by leaving the intercalary day of leap year out, they were able to achieve this.
