Bernardino de Sahagún (Sahagún, Spain, c. 1499 - Tlatelolco, Mexico, February 5, 1590) was a Franciscan missionary, author of several works in Nahuatl and Spanish, considered today among the most valuable documents for the reconstruction of history of ancient Mexico before the arrival of the Spanish. Among his writings stands out the General History of Things of New Spain, a true ethnographic monument, made up of twelve books, which hardly has comparable precedents in any language. Sahagún was, in the opinion of Jerónimo de Mendieta, the most expert of all in the Nahuatl language.