I begin with a paradox. Our best evidence for the use of medieval religious art-that is, what most of us would think of as 'Catholic' art-survives in Protestant Germany. In Saxony and Lower Saxony alone, 545 medieval altarpieces survive in their churches; Mecklenburg has another 165. 1 There are more medieval mass chalices extant today from northern Germany than from anywhere else; the number may exceed 1000. Winged altars, rood screens, embroidered frontals and other church furnishings have also been preserved there in large numbers, often in their original liturgical settings. 2 The richest collection of medieval chasubles is found in Lutheran Germany, and many more survive in Lutheran churches in Hungary and Poland. 3 Such chalices, altar linens and altarpieces are not, for the most part, preserved in display cases; they are used * An early version of this paper was presented as the James Field Willard lecture at the University of Colorado at Boulder on October 23, 2014. I am grateful to Profs. Scott Bruce and Anne Lester for the invitation to Colorado and to the many helpful suggestions I received at the conference on 'Medieval Materiality' that followed on October 24 and 25. I also thank Richard Kieckhefer, Denise Koller, Guenther Roth, and two anonymous readers for German History for valuable suggestions. As always, I am grateful to Jeffrey Hamburger and Henrike Lähnemann for guiding me through materials from the Lüneburg cloisters and for their wide-ranging researches in the archives and libraries of the region.