Final Published Version
Eight third-century Ionic capitals with images of Isis, Serapis, and Harpocrates, now in the nave colonnades of Sta. Maria in Trastevere, were taken from one or both of the rooms currently identified as libraries in the Baths of Caracalla. The capitals were transferred around 1140, when the church was rebuilt by Pope Innocent II. The capitals would have been acquired by confiscation, juridically the pope's prerogative as head of the papal state; the lavish display of all kinds of spolia in Sta. Maria in Trastevere is here interpreted as a self-conscious demonstration of that prerogative. The identity of the capitals' pagan images would have been unknown to most twelfth-century observers, because the only accessible keys to the correct identifications were one sentence in Varro's De lingua latina and another in Saint Augustine's De civitate Dei. Philological accuracy in interpretation is an anachronistic expectation in any case; medieval readings of the images would have been fanciful, based on associations unexpected from a twentieth-century point of view.
Kinney, Dale. 1986. " Spolia from the Baths of Caracalla in Sta. Maria in Trastevere." The Art Bulletin 68.3: 379-397.