Perhaps no other relic of the European Middle Ages captures our imagination more than illuminated medieval manuscripts, or those documents decorated with images and colored pigments. Serving as windows unto a lost world of kings, ladies, faith, war, and culture, they communicate complex visual and textual narratives of Europe’s collective cultural heritage and patrimony. In this fashion, illuminated manuscripts are dynamic messages from our communal past that are still relevant today in fields like graphic design and typography. In this seven-week course, students will explore the material creation, content, and historical context of illuminated medieval European manuscripts. Students will acquire an introductory knowledge of their distinguishing characteristics, their cataloguing and periodization (when they were created), the methods utilized to produce them, and their historical context and value. Student achievement will be assessed using not only traditional multiple-choice quizzes, but more importantly will be evaluated based on individual student projects. In their final projects students will either (1) produce a board of commented images about medieval manuscripts or (2) prepare a physical manuscript using medieval methods. The best of these peer-evaluated projects will be posted on the Deciphering Secrets website, which is our collective citizen scholarship web presence that encourages and supports our global citizen scholars appreciation and contributions to transcription of medieval manuscripts. Finally, we wish to highlight that this course is an exciting international collaboration between the University of Colorado (USA) and Universidad Complutense Madrid (Spain).