There had been Zapotec and Mixtec settlements in valley of Oaxaca for thousands of years, especially in connection with the important ancient centers of Monte Albán and Mitla, which are close to modern Oaxaca city. The Aztecs entered the valley in 1440 and named it “Huaxyacac,” a Nahuatl phrase meaning "among the huaje" (Leucaena leucocephala) trees. A strategic military position was created here, at what is now called the Cerro (large hill) del Fortín to keep an eye on the Zapotec capital of Zaachila and secure the trade route between the Valley of Mexico, Tehuantepec and what is now Central America. When the Spanish arrived in 1521, the Zapotecs and the Mixtecs were involved in one of their many wars. Spanish conquest would end this fighting.
The first Spanish expedition here arrived late in 1521, headed by Captain Francisco de Orozco, and accompanied by 400 Aztecs. Hernán Cortés sent Francisco de Orozco to Oaxaca because Moctezuma II said that the Aztec’s gold came from there. The Spanish expedition under Orozco set about building a Spanish city where the Aztec military post was at the base of the Cerro de Fortín. The first mass was said here by Chaplain Juan Diaz on the bank of the Atoyac River under a large huaje tree, where the Church of San Juan de Dios would be constructed later. This same chaplain added saints’ names to the surrounding villages in addition to keeping their Nahuatl names: Santa María Oaxaca, San Martín Mexicapan, San Juan Chapultepec, Santo Tomas Xochimilco, San Matías Jalatlaco, Santiago Tepeaca, etc. This group of Spaniards chose their first mayor, Gutierres de Badajoc, their first town council and began construction of the cathedral of Oaxaca in 1522. Their name for the settlement was Guajaca, a Hispanization of the Nahuatl name (which would later be respelled as Oaxaca).
The establishment of the relatively-independent village did not suit Hernán Cortes, who wanted power over the entire region for himself
