If your interests lie in Late Antiquity and the Middle Ages, Michael Greenhalgh's online textbook is a marvel--and currently out of print in paperback or hard cover. The authors works include: The Classical Tradition in Art; Marble Past, Monument Present: Building with Antiquities in the Mediaeval Mediterranean, among others. Fans of the use of Roman spolia in the Middle Ages will find this a very interesting read. The survival of ancient manuscripts from the Greco-Roman world is also treated. N.B. this online version does not contain any images. I found the link while searching the terms "pantheon and spolia."
http://rubens.anu.ed...rvival.publish/
From the Introduction:
This book enquires into what classes of artefacts, from gems to villas, were
available in the West for all or part of the Middle Ages - a period which I
take to be from roughly 500 AD to 1400 AD. It is partly an interpretative
`biography' of various classes of antiquities during that period, and partly an
examination of the circumstances leading to their survival, destruction or
rediscovery. In this context antiquities are defined as structural remains and
objects which have an `artistic' context - that is, sculptural friezes or coins
rather than ploughshares or other utilitarian objects. The survey is not
confined to pagan objects: paleochristian works are included, not simply
because of the revivals of Early Christian work in later centuries (e.g.
Bergman 1974, 171ff.), but also because the Middle Ages sometimes made no clear
distinction between pagan and Christian. Each observation the book contains is
supported by only a few examples (based on documents and other published
material) which could, of course, easily be multiplied by anyone wishing to
pursue particular topics in greater depth than is appropriate in such a broad
survey as this. Background to the earlier Middle Ages is provided by
Ward-Perkins (1984), who discusses changes in the tradition of public building
- one essential measure against which to view the survival of the antique.