Marble floors and inlay decorations originated in the classical period; better known as opus sectile pavements and opus interrasile wall decorations, they are common features of such medieval temples as churches and mosques in the Mediterranean area. While a good number of studies have explored this medieval phenomenon since the last century onward, the pioneering Studies on Cosmatesque Pavements by Dorothy F. Glass published in 1980 represented a turning point in the methodological approach toward a topic that had previously been considered a single and isolated artistic phenomenon, serving as a geometrical and ornamental element subordinate to other figurative decorations and visual media. Through a historiographic overview, tracking the main contributions – from the first attempts in the early XX century until the ongoing Corpus Cosmatorum directed by Peter Cornelius Claussen – I pinpoint the potential clues and insights still offered by Glass’ work and approach, thanks to which it is possible today to think of medieval marble decorations as one of the main components of the architectural design of monuments and physical spaces. This holistic approach – already experienced in Glass’ studies – allows us to conceive of the geometrical inlaid marbles as distinctive decorations that – like sculpture – characterized liturgical spaces and furnishings and created what we can identify as the sacred space in the medieval Mediterranean world.

In her seminal work, Studies on Cosmatesque Pavement — published in 1980, but an outgrowth of her 1968 dissertation — Dorothy F. Glass demonstrated a methodological approach that signaled the manner in which her inquiry would shape and inspire those interested in Italian medieval architectural space. On the one hand, this study, deeply grounded in archaeological analysis, provided a compendium of a specific type of architectural articulation and practice – the “cosmatesque” floor. On the other, it was ground breaking in the manner in which it suggested that the very elements of medieval construction could – and did – activate an ideological association of the spaces it created. Her investigation was unusual, furthermore, in that it not only considered the grand papal monuments so often exclusively considered in the field, but also included smaller, nondescript and little studied monuments, reflecting the body of material produced in the medieval period. This study thus stood as a precursor to the hallmark of Glass’ work – the intrinsic role that architectural elements, from monuments within and outside the canon, played in activating and shaping sacred space. This paper returns to a fundamental tension in Glass’ Studies on Cosmatesque Pavements, a tension that pervades the study of Rome’s twelfth-century monuments. When is a pavement a means of sculpting ideological association, and when is a pavement just a pavement? It situates Glass’ inquiry within her formation as a scholar in the late 1960s and the questions of representation marked by Foucault’s 1968 essay, “This is Not a Pipe.” Yet, it suggests that the answers lie in the breadth of Glass’ methodological approaches, in particular her willingness to deconstruct a singular narrative in favor of a multiplicity of associations that speak to the complexity of the creation of medieval sacred space.