What is the Aztec Xiuhpohualli?

The xiuhpohualli structured the annual ceremonial cycle and interlocked with the ritual 260-day count.

How the calendar is structured

365-day annual cycle commonly described as 18 periods of 20 days plus 5 extra days.

Where and why it is used

Region: Central Mexico. Primary context: Historical and cultural study.

History and development

The system belongs to the Ancient layer of the archive. Its origin is summarized as Pre-Columbian. CalculatorWiser separates historical reconstruction, religious observance, civil use, and modern technical standards so different systems are not treated as though they all work the same way.

Visual reference gallery

Conversion and accuracy notes

Some calendar systems can be converted deterministically with modern algorithms. Others depend on observation, local authority, historical reconstruction, or regional practice. CalculatorWiser marks those distinctions rather than presenting uncertain dates as exact.

Research trail

This entry is part of the research-backed World Calendar Archive. Primary research anchor for this entry: Mesoamerican calendar references.