While few non-historians may be expected to be familiar with his name, his relevance for the pre-Hispanic history and culture of México cannot be easily stated with words, being essentially the first and greatest real life counterpoint to every modern portrayal of the Spanish conquest as a destruction and erasure of native culture. During a 60 year career in New Spain, modern México, Sahagún dedicated himself to evangelize Mexican natives in the Catholic faith while at the same time working to cram all the available knowledge, worldview and culture of Aztecs, Tlaxcaltecs and every civilization he could reach, ultimately achieving his magnum opus with the massive, 12-volume work Historia general de las cosas de la Nueva España, written and illustrated by the hands of the natives themselves, which was officially declared World Heritage by the UNESCO in 2015.
Born in Sahagún, continental Spain, Bernardino studied in the University of Salamanca, where he absorbed Erasmus' humanism and was very likely influenced by the inter-cultural postulates of the School of Salamanca, as he was contemporaneous with many of its members. He was ordained a Franciscan friar in 1527, dropping his surname by his city of birth, and two years later he was selected to travel as a missionary to New Spain, where Hernán Cortés had recently secured the Spanish Conquest of the Aztec Empire. He passed many years teaching Latin to the sons of the indigenous aristocracy in the Colegio de la Santa Cruz of Tlatelolco, an intellectual center where Christian and Amerindian culture blended, and it was there where Bernardino and other professors started recruiting their own students to help record the indigenous life and world. Amerindian herbology and medicine were one of their first interests, and Sahagún himself may have helped the native healers-turned-converts Martín de la Cruz and Juan Badiano to write their monumental treatise on Mexican herbology (the task of researching this field would take decades, though, with scientists like Francisco Hernández de Toledo and Nicolás Monardes being sent there from Spain to speed things up).
In his breaks, Bernardino also did himself missionary work in places like Xochimilco, Huexotzingo and Cholula, where he had the chance to exercise his knowledge of the local Nahuatl language. The Spanish church's official policy was that the indigenous should be preached in their own mother tongues, which was infinitely easier than trying to teach and get an entire continent to speak Spanish, and Bernardino had the chance to study them back in Spain. He authored texts in both languages, especially translating religious texts from Spanish to Nahuatl, but he also translated from Nahuatl to Spanish, with the most interesting being a treatise of Aztec huehuetlatolli philosophy and pedagogy. In 1558, his research received full official support from the local branch of the church for being their greatest expert in native culture, a field they needed to master to ease evangelization, and essentially gave him free hand. Bernardino and his team of native students of Tlatelolco spent years interviewing village elders about their religious rituals, calendar, family, economic and political customs, and natural history, and also had native artists drawing illustrations, an early example of the mixed Spanish-indigenous style of religious art named indocristiano.
Towards the end of his life, his writings reveal a certain despair due to the conquest' changing conditions. Aside from the usual European diseases, who constantly decimated the native population and killed friends and coworkers, he initial wave of conquistadores and religious orders were being gradually replaced by Spanish administrators and clergymen who had not lived, slept and bled with the indigenous during the conquest, and therefore weren't as enthusiastic about making their life easier. To worsen things, although King Philip II was fan of Bernardino's work to the point of declaring Nahuatl an official Spanish language, he then removed anthropological literature from public access in 1577 and even temporarily barred mestizos from Catholic priesthoodnote probably because the course of the war against Protestantism had convinced him that airing out pagan culture could risk generating yet another heresy in his empire. The result is that many of Sahagún's works languished in royal archives after his death in Tlatelolco in 1590, and would only be released gradually over the centuries, the last of them in 1905, after the Spanish Empire itself had disappeared.
In any case, the legacy of Bernardino and his colleagues and students remains a true cultural treasure. Almost every field of all the Pre-Hispanic Mexican culture we know today, including Aztec Mythology, has some contribution taken from his corpus, and in several cases his corpus comprises it entirely - a lot of ancient-looking Aztec artwork you can find on the Internet was actually drawn by native artists after the conquest thanks to their efforts. He even cared to avert Written by the Winners by arranging in 1554 to record the visión de los vencidos, the Spanish conquest seen from the point of view of the defeated Mexica Empire, even if he had to take care the text would not sound subversive to the Spanish crown. Although he is not free of postmodern criticism, especially regarding that all the indigenous preservation of their worldview comes still ultimately filtered by Christian authority, what Bernardino and his people did was an almost unique event of in the human history - no previous empire, and likely no posterior western power either, made an effort this big and thorough to learn and preserve the culture of their assimilated peoples, almost like an intangible reflection of the mestizaje that was happening across their new world.
Although Sahagún might have died with the impression that his work was All for Nothing, modern academia still remembers him as one of most important ethnographers and history and an indispensable figure in our knowledge of Central America.
