Two states in Mexico claim to be the origin of mole: Puebla and Oaxaca The best-known moles are native to these two states, but other regions in Mexico also make various types of mole sauces.
Moles come in various flavors and ingredients, with chili peppers as the common factor. However, the classic mole version is the variety called mole poblano, which is a dark red or brown sauce served over meat. The dish has become a culinary symbol of Mexico’s mestizaje, or mixed indigenous and European heritage, both for the types of ingredients it contains and because of the legends surrounding its origin.
A common legend of its creation takes place at the Convent of Santa Clara in Puebla early in the colonial period. Upon hearing that the archbishop was going to visit, the convent nuns panicked because they were poor and had almost nothing to prepare. The nuns prayed and brought together the little bits of what they did have, including chili peppers, spices, day-old bread, nuts, and a little chocolate. They killed an old turkey, cooked it and put the sauce on top; the archbishop loved it. When one of the nuns was asked the name of the dish, she replied, "I made a mole." Mole was the ancient word for mix; now this word mostly refers to the dish, and is rarely used to signify other kinds of mixes in Spanish.
A similar version of the story says that monk Fray Pascual invented the dish, again to serve the archbishop of Puebla. In this version, spices were knocked over or blown over into pots in which chicken were cooking. Other versions of the story substitute the viceroy of New Spain, such as Juan de Palafox y Mendoza in place of the archbishop.
Modern mole is a mixture of ingredients from North America, Europe and Africa, making it one of the first intercontinental dishes created in the Americas. Its base, however, is indigenous. Nahuatl speakers had a preparation they called mōlli ([ˈmoːlːi]), meaning "sauce", or chīlmōlli ([t͡ʃiːlˈmoːlːi]) for chili sauce. In the book General History of the Things of New Spain, Bernardino de Sahagún says that mollis were used in a number of dishes, including those for fish, game and vegetables. Theories about the origins of mole have supposed that it was something imposed upon the natives or that it was the product of the baroque artistry of Puebla, but there is not enough evidence for definitive answers. Coincidence or not, the word "mōlli" seems to resemble the Portuguese word molho, which means "sauce".
While chili pepper sauces existed in pre-Hispanic Mexico, the complicated moles of today did not. They did not contain chocolate, which was used as a beverage, and in all of the writings of Sahagún, there is no mention at all of it being used to flavor food. Most likely what occurred was a gradual modification of the original molli sauce, adding more and different ingredients depending on the location. This diversified the resulting sauces into various types. Ingredients that have been added into moles include nuts (such as almonds, peanuts, or pine nuts), seeds (such as sesame seeds, pumpkin seeds, or squash seeds), cilantro, seedless grapes, plantains, garlic, onions, cinnamon, and chocolate. However, most versions do not contain cinnamon or chocolate. What remained the same was the use of chili peppers, especially ancho, pasilla, mulato and chipotle, and the consistency of the sauce. The true story of how mole developed may never be truly known, as the first recipes did not appear until after the Mexican War of Independence in 1810. The Nahuatl etymology of the name probably indicates a Mesoamerican origin.