The history of the town and municipality begins about 1500 years ago at an elevation now named “Cerro de Murciélago” or Bat Mountain. The hill contained two caves that used to be filled with thousands of bats. The presence of these animals was considered a sign of fertility. The hill remained populated until the 18th century, when a plague pushed the population toward the Franciscan monastery, which functioned as a hospital. A deity named Zinacan was associated with the mountain. Shortly after the Spanish Conquest, this deity would be believed to be an incarnation of the Devil. Today, the bat population of the area is limited to a few caves in the Nevado de Toluca National Park. The mountain is mined for gravel and alongside it is the Hacienda de Santa Cruz de los Patos, which is now part of the Mexiquense College, as a research center and library.