The Post-Classic period dates from 1000 CE and ends with the arrival of Europeans in 1519. During this period the region was populated with tiny kingdoms, called señorios and cacicazgos, which were centered on prior urban centers. At this time the Mixtec experienced their greatest population, though there was a decline in monumental urban projects; areas and structures were being maintained and reused, while new ceremonial centers and projects were less numerous and less impressive. Despite this, the Mixtec were a source of influence for Mesoamerica during this period. The archaeological record has produced evidence of neighboring regions influencing Mixtec art and culture in the periods prior, while during the Post-Classic the role was reversed, with Mixtec influences permeating the region and the neighboring cultures. This sharing of culture is also found in the writing systems of pre-Columbian Mesoamerica, as phonetic elements and symbols operated across cultures.