The research that this book collects and analyzes began in 2010 and has evolved significantly since that nascent moment, well over a decade ago. My path toward the codex then known as the Thun’sche Skizzenbuch (or Thun Sketchbook) was nonlinear and unexpected. It began with a modern reproduction of a late medieval work: a breastplate made by an armorer (perhaps Lorenz Killian, d. 1919, or Leonard Hugel, 1877–1935) working in Munich for an art dealer, armorer, and sometime-forger named Ernst Schmidt (active ca. 1868–at least 1928) during the late-nineteenth or early-twentieth century. This modern smith copied a piece of armor that Lorenz Helmschmid (active ca. 1467–1515/16) crafted for Maximilian I (1459–1519) during the 1480s. As a young graduate student and curatorial assistant, I stumbled upon this object – its charisma undimmed by its revivalist origins – hanging on a painting rack in a remote storeroom corner of the Spencer Museum of Art in Lawrence, Kansas. Though I, like many fledgling medievalists, had long admired the “knights in shining armor” displayed in museum galleries or depicted in books, art, and film, my intended area of scholarly focus at the time was the entanglement of early print culture with precious metalwork. However, the breastplate and, especially, its fifteenth-century antecedents exerted a centripetal force. A metalsmith, steel fabricator, and glass worker by training, I had spent my undergraduate years learning the sculptural techniques of torch, welder, and furnace alongside studies in the histories of art and of medieval and early modern Europe. Armor seemed to encompass all my interests at once and I saw the echoes of familiar processes in the marks of hammer and file that traversed the object and the delicately pierced patterns that adorned it.

I felt compelled to learn everything I could about the breastplate's late-gothic model and its maker, as well as the histories and forms of arms and armor more broadly. This exploration quickly led me to early scholarship on the Thun’sche Skizzenbuch published by Ortwin Gamber over a decade after the codex had vanished at the end of World War II. I traveled to Vienna to view the inimitable yet widely copied Helmschmid armors that had inspired both the images in the so-called sketchbook and Schmidt's reproduction breastplate in Kansas. In Augsburg, I poured over glass plate photographs of the book's drawings that were believed to be the last vestiges of this lost source.