What is now the historic downtown of Mexico City roughly correlates with the ancient Aztec city of Tenochtitlan, which was founded around 1325. During the prehispanic era, the city developed in a planned fashion, with streets and canals aligned with the cardinal directions, leading to orderly square blocks. The island that the city was founded on was divided into four calpullis or neighborhoods that were divided by the main north-south roads leading to Tepeyac and Iztapalapa respectively and the west-east road that lead to Tacuba and to a dike into the lake, respectively. The calpullis were named Cuepopan, Atzacualco, Moyotla and Zoquipan, which had subdivisions and a "tecpan" or district council each. The intersection of these roads was the center of the city and of the Aztec world. Here were the Templo Mayor, the palaces of the tlatoani or emperors, palaces of nobles such as the "House of the Demons" and the "House of the Flowers". Also located here were the two most renowned Aztec schools: the Telpuchcalli for secular studies and the Calmecac for priestly training. When the Spaniards arrived, the city had aqueducts built by Moctezuma Ilhuicamina and Ahuizotl as well as a large dike constructed to the east of the city.