According to a legend, the Aztecs would found a great city there where they found an eagle devouring a snake, perched on a cactus. In the year 1325, the Aztec priests discovered this scene on an islet near Lake Texcoco, and there they built the city called Tecnochtitlán. At the time of its highest development, the Aztec Empire extended through what is now the central region of the country, from the coast of the Gulf of Mexico to the Pacific coast, and from the Bajío to Oxaca. Aztec empire. Tenochtitlan. Peoples of Mesoamerica