At the time the Spanish conquered the Aztec Empire, the Toluca Valley was a tribute-paying area and buffer zone between the Aztec and Purépecha empires. Gonzalo de Sandoval conquered most of the area for the Spanish along with Otomi allies. Hernán Cortés’ cousin Juan Altamirano was given dominion of the Toluca Valley. Franciscan missionaries came soon after, such as Martin de Valencia, Juan de Tecto, Juan de Ahora, and Pedro de Gante, who established missions and the first school called San Antonio de Padua. Spanish colonial territorial rule was based on the pre-conquest jurisdictions. Former city-states were defined as "cabeceras" (head-towns). The former Aztec empire became the "audencia" of Mexico; it was centered on Mexico City and expanded over the Toluca Valley, and further south and west into the modern states of Guerrero and Morelos.