 The great cities that dominated Petén had fallen into ruin by the beginning of the 10th century AD with the onset of the Classic Maya collapse.A significant Maya presence remained in Petén into the Postclassic period after the abandonment of the major Classic period cities; the population was particularly concentrated near permanent water sources.In the early 16th century, when the Spanish discovered the Yucatán Peninsula, the region was still dominated by the Maya civilization.