A centuries-old document that tells the story of the Aztec civilization and its decline after the arrival of the Spanish conquistadors is going on display in Mexico for the first time in 186 years. The manuscript, known as the Codex Azcatitlán, was created in the 16th century—just a few years after the Spanish arrived in what is now Mexico. It is considered one of the most valuable and detailed records of Aztec history, using pictograms, or images, to convey its message. The codex has been held in France’s Bibliothèque Nationale since 1898, but it had spent decades outside of Mexico before that. Now, it will be displayed in Mexico as part of a cultural exchange between the two countries. The temporary display of the Codex Azcatitlán in Mexico marks 200 years of Franco-Mexican relations. In return, Mexico has agreed to lend France another important document, the Codex Boturini, for display in France. This codex, also made with pictograms, narrates the migration of the Aztecs—also known as the Mexica—from their ancestral homeland to the shores of Lake Texcoco, where they eventually built their capital, Tenochtitlán. The exchange of these two codices was agreed upon by Mexican President Claudia Sheinbaum and French President Emmanuel Macron during Macron’s visit to Mexico last year. Mexico has long sought the return of historical artifacts taken from the country during past centuries. According to Mexico’s Ministry of Foreign Relations, more than 2,000 objects were successfully returned to the country last year. This exchange is part of an ongoing effort to repatriate cultural heritage and strengthen diplomatic ties with other nations. The Codex Azcatitlán will be on display at the National Museum of Anthropology in Mexico City starting this Thursday, offering the public a rare opportunity to view one of the most important documents of pre-Columbian history.