Mesoamerican astronomers developed a complex, highly sophisticated calendar anchored to seasonal events. It is a living system for tracking the movement of the sun across the horizon. By utilizing this calendar, you are helping to maintain a time-keeping tradition that stretches back thousands of years across Mesoamerica. A tradition that has been passed down through the ages, and which has much to teach us in these modern times. I hope you find this calendar to be a useful part of your daily routine.