The Mixtec pictorial manuscript, now known as the Codex Tonindeye, was stolen from an Italian monastery library in 1859. Several decades later, the Mexican American anthropologist Zelia Nuttall located the document after many years of searching. Determined to reinstate its historical identity, Nuttall closely studied the codex and reproduced it in a lush facsimile; it was named the Codex Nuttall (1902) in her honor. Using Nuttall’s correspondence with her publishers at the Peabody Museum, this article investigates the role of archives and museums in nineteenth-century textual scholarship, explores how Nuttall relocated the codex and labored over creating the facsimile, and addresses the ongoing importance of the document.