Time isn’t just what ticks on a wall — it’s what civilizations carve into the cosmos. This presentation explores the fascinating, often overlooked world of non-Gregorian calendar systems from around the globe. From the meticulous astronomical cycles of the Mayan Long Count to the poetic moon-chasing rituals of the Tamil calendar, we journey through the human urge to define, control, and make meaning out of time.

1. Architecting Time: Calendars
Beyond the Gregorian
An educational presentation on
global calendar systems

2. What Is a Calendar?
• Organizes days for religious, social, and
agricultural purposes.
• • Typically based on solar, lunar, or lunisolar
cycles.
• • Shapes how cultures record time and
history.

3. Why the Gregorian Calendar Isn't
Universal
• Introduced in 1582 by Pope Gregory XIII.
• • Based on solar year — doesn’t align with
moon phases.
• • Other cultures follow different timekeeping
methods.

4. The Mayan Long Count
• Used by ancient Mayans to track centuries.
• • Includes baktuns, katuns, and other units.
• • Highly accurate astronomical knowledge.

5. The Hebrew Calendar
• Lunisolar: combines moon phases with solar
year.
• • Used to calculate Jewish festivals.
• • Adjusts with a leap month every few years.

6. The Tamil Calendar
• Used in Tamil Nadu and Sri Lanka.
• • Lunisolar and tied to Hindu astrology.
• • Determines religious festivals and rituals.

7. The Ethiopian Calendar
• Has 13 months: 12 of 30 days, 1 of 5–6 days.
• • New Year starts in September.
• • Runs 7–8 years behind Gregorian.

8. French Revolutionary Calendar
• Created during French Revolution to replace
Gregorian.
• • Featured 10-day weeks and decimal time.
• • Abandoned due to public resistance.

9. Agriculture and Calendars
• Ancient calendars synced with crop cycles.
• • Festivals aligned with sowing and harvest
seasons.
• • Still used in many farming communities.

10. Timekeeping as Political Power
• Colonial powers enforced Gregorian time.
• • Standard time zones helped manage
empires.
• • Changing calendars was a sign of
independence.

11. Create Your Own Calendar
• Pick a base (solar/lunar/lunisolar).
• • Define your own months, weeks, and
festivals.
• • Useful for fiction, rituals, or personal
systems.

12. Conclusion: Rethinking Time
• Calendars are more than dates — they hold
meaning.
• • Every culture offers a unique view of time.
• • Learning others’ time systems builds
empathy.