Opening passage of Stefan Roller's The Polychromy of Mediaeval Sculpture: A Brief Overview,

"A problem which Mediaeval art history shares with classical archaeology is that the modern viewer has little awareness of the fact that the sculpture was originally polychrome in appearance. This is all the more surprising when one considers that, in the Mediaeval departments of museums and in many churches, we are not faced with gleaming, bare marble figures as in most collections of ancient art: instead, many sculptures have survived with more or less extensive remnants of polychromy. In some cases, indeed, we are able to admire the original polychromy in a very good state of preservation. All the same, it still comes as a surprise to many museum visitors to be told that at all stages of the Mediaeval period the majority of figures and reliefs owed much of their visual impact to their polychrome finish. Nor is this loss of understanding of the original totality of a sculpture - which, after all, as originally conceived, comprises both its sculptural form and its polychromy - by any means limited to laypersons. There are still far too many art professionals for whom only the sculptural form of a figure counts, and who regard colour as, at best, a decorative secondary feature, or sometimes even a hindrance, when it comes to the appreciation of the artwork itself."

Roller, Stefan. “The Polychromy of Mediaeval Sculpture: A Brief Overview.” In Circumlitio: The Polychromy of Antique and Mediaeval Sculpture. Munich: Hirmer Verlag, 2010.