Mesoamerican Long Count calendar the use of zero as a place-holder and presents one of the earliest uses of the zero concept in history. On Maya monuments, the Long Count syntax is more complex. The date sequence is given once, at the beginning of the inscription and opens with the so-called ISIG (Introductory Series Initial Glyph) which reads "tzik-a(h) hab’ [patron of Haab' month]" ("revered was the year-count with the patron [of the month]"). Next come the 5 digits of the Long Count, followed by the Calendar Round (tzolk'in and Haab') and supplementary series. The supplementary series is optional and contains lunar data, for
Calendar year and Q4. When combined with a year, the quarter/year combination may be written, for example, as Q42019 or 4Q2019 or 2019Q4. Calendar year Generally speaking, a calendar year begins on the New Year's Day of the given calendar system and ends on the day before the following New Year's Day, and thus consists of a whole number of days. A year can also be measured by starting on any other named day of the calendar, and ending on the day before this named day in the following year. This may be termed a "year's time", but not a "calendar year".