Galilean moons century when other inner moons were discovered, and Marius' names became widely used. Galileo was able to develop a method of determining longitude based on the timing of the orbits of the Galilean moons. The times of the eclipses of the moons could be precisely calculated in advance, and compared with local observations on land or on ship to determine the local time and hence longitude. The main problem with the technique was that it was difficult to observe the Galilean moons through a telescope on a moving ship; a problem that Galileo tried to solve with the invention of
El Conde prior to the Teotihuacan, Toltec, Chichimeca, and certainly the Aztec. In the Mesoamerican Preclassical period (1300 to 1400 BCE), an Olmec group arrived and had a significant influence on the Tlatilca domain. Later, the Tlatilca were also heavily influenced by the Teotihuacan civilization. Between 1000 and 1200 CE, the Chichimeca conquered the Tlatilca and deposed their monarchy. The pyramid of El Conde was built during this time, located in what is now the El Conde neighborhood. Subsequently, the area was ruled by Tlacopan and ethnically came to be dominated by the Otomies. As of 1428 CE, the area was under