The Mixtec are an indigenous people of Mesoamerica, located in the western region of the modern Mexican states of Oaxaca, eastern part of Guerrero, and southern part of Puebla. The history of the Mixtec people can be traced back to the Formative period, and continues through the Classic and Post-Classic periods to the arrival of Europeans in 1520 AD. Today the region is still populated by the Mixtec and Mixtecan speakers. During the 2500 years before the arrival of Europeans, the Mixtec developed complex social and economic traditions, effectively exploited their diverse environment, created a method of writing, and maintained their autonomy from other civilizations, such as the Aztecs.