 The volcano is also referred to by Mexicans as "El Popo".The alternate nickname "Don Goyo" comes from the mountain's association in the lore of the region with San Gregorio, "Goyo" being a nickname-like short form of Gregorio.Legend says that many years ago, a villager met an old man on the slopes of the mountain, who introduced himself as Gregorio Chino Popocatépetl.