Teachers know how difficult it can be to challenge what students believe they already know. Conveying new information may not always be easy, but the resistance of “Why should I care?/How is this relevant to my life?” is nothing compared to that entailed in questioning the knowledge already stored safely away in memory. It seems human nature to prefer validation of what is already known to cleaning the slate so as to make room for something different. What everyone knows, few might think to question. This has always been a problem, and to challenge received wisdom can be unrewarding, but scholarship does-sometimes, to be sure, in fits and starts-move, and knowledge changes. As Tom Noble wrote recently in his introduction to an extraordinarily useful and thoughtful translation of the five extant lives of Charlemagne and Louis the Pious, even well-known “facts” can be challenged, especially by careful source criticism that takes into account the purposes and audiences and transmission of apparently historical reports.1 Tom Noble is a teacher, and by all accounts a truly great one, and I offer this attempt to challenge what everyone seems to think they “know” about a famous Carolingian manuscript as a grateful tribute to his inspiring example. He is the most art-historical of historians, and his great book Images, Iconoclasm and the Carolingians provides a fundamental basis for anyone interested in what he aptly termed “art talk” of the period. The task remains to address the art of the period with these new insights.2 Tom’s scholarship is always precise, wonderfully clearly and concisely presented, and based on the sources. What do we know, and how do we think we know it?