1. AZTEC CALENDER BY: ANTHONY CABRERA Period. 3 pre-calculus

2. HISTORY The Aztecs, or Mexica as they called themselves, were the elite of a militaristic empire focused in Central Mexico when the Spanish conquistadores landed in America at the beginning of the 16th century CE. The Aztecs originated in the semi-arid environments of northern Mexico as one of the many barbarian or "Chichimec" tribes. They arrived at the fertile Valley of Mexico most likely during the 14th century CE, and found the land already settled and divided by city states. They built their city at the marshes of Lake Texcoco, and quickly adopted much of the culture and language of their new neighbors.

3. WHAT IS THE AZTEC CALENDER? The Aztec calendar is the CALENDAR system that was used by the AZTECS as well as other PRECOLUMBIAN peoples of central MEXICO. It is one of the MESOAMERICAN CALENDARS, sharing the basic structure of calendars from throughout ancient MESOAMERICA. It’s recognized as the world's most accurate calendar, more so than the Gregorian system (based on the Julian calendar) that we use today.

4. HOW MANY AZTEC CALENDERS ARE THERE? There were actually two Aztec Calendars and they were both based on the MAYAN CALENDARS. One of them, called the Xiuhpohualli Calendar consisted of 365 days and was used for farming and normal daily life. The other, known as The Tonalpohualli, had 260 days and was used for worship and observing rituals. This calendar, the name means 'day count' in English, is the one described first.

5. The Tonalpohualli - the Aztec Sacred Calendar Each day has both a number and a symbol and both are needed to define the date. The numbers run from 1 to 13 and there are 20 different symbols. Day one is defined by number 1 and symbol 1. Day two is defined by number 2 and symbol 2. This continues until day 13 which is defined by number 13 and symbol 13. Day 14 is defined by number 1 and symbol 14, day 15 by number 2 and symbol 15. Day 20 is defined by number 7 and symbol 20. Day 21 by number 8 and symbol 1. As 13 is not a factor of 20 the same pair do not re-occur for 260 days and then a new sacred year starts.

6. The Xiuhpohualli - The Aztec Seasonal Calendar? This calendar defines a year of 18 months, each of 20 days, and five extra days, 365 days in total. These extra days were considered unlucky and so very little was done on them. Each year had a name and number combination as did the days in the The Tonalpohualli but this time there were only 52 such combinations before repeating. This series was known as a 'bundle'.

8. DAY SIGNS Day signs The set of day signs used in central Mexico is identical to that used by Mixtecs, and to a lesser degree similar to those of other Mesoamerican calendars. Each of the day signs also bears an association with one of the four cardinal directions.