Toltec mathematics and time measuring
Mathematics was a fundamental knowledge field of our ancestors. It was necessary not only for construction of monumental and exquisite knowledge centers, but in the field of calendars and time measurement. Indeed, the Mayans invented the mathematical zero, and in their calendar measurements the figures are both incredible and perfect. Our ancestors had three different calendars, the three assembled into a perfect one. The first was 260 days and in relation to the Moon. The second was 365-¼, related to the earth orbital movement around the Sun. The third was 52 years and was perfectly synchronized with the earth orbital movement around the group of stars called "The Pleiades" or Seven Sisters (Messier object 45). Also the Venus cycle.
"We also know the relationship that exists between the architectural disposition of Teotihuacan and the passing of the Pleiades zenith every 52 years, as a big year in the Taurus constellation, this great year is the time at which both counts join: the 260-day ritual that relates to Venus and Earth orbits, and solar agricultural of 365.25 days, which happens every 18,980 days, i.e. one Xiuhmolpilli." (Maria Elena Romero Murguía. 1988)