Aztec astrology is one of the earliest Mesoamerican system that was developed independent of other astrology systems. The Aztecs were very much interested in the study of the cosmos. The Aztec calendar is known as the tonalpohualli and consists of 260 days. This system has 20 day signs each ruled by a God/ Goddess. These day signs describe the characteristics of the person born under the sign. This form of astrology follows a 260-day Aztec calendar, also known as the tonalpohualli, divides the time between gods/ goddesses of the opposing forces, thus giving a special quality to each of the days of the calendar. Based on a 13-day cycle, there are 20 Aztec day signs. Each of the twenty zodiac signs of Aztec astrology are ruled over by a particular god/ goddess which in turn represents the personality and the characteristic traits of the native born under a particular zodiac. The twenty zodiac signs of the Aztec Astrology are as follows: Cipactli, Ehecatl, Calli, Cuetzpalin, Coatl, Cimi, Manik, Tochtli, Atl, Itzcuintli, Ozomahtli, Malinalli, Ben, Ocelotl, Cuauhtli, Cib, Ollin, Tecpatl, Cauac and Xochitl.