Carving on the back reveals that this slab was from a lintel of an earlier, perhaps Roman, monument. Older sculptural fragments can also be seen in the adjacent doorway from San Gemini.
Robert Forrer, Colmar (sold 1909)
Gómez-Moreno, Carmen. Medieval Images: A Glimpse into the Symbolism and Reality of the Middle Ages. Katonah: Katonah Museum of Art, 1978. no. 4, pp. 5, 17.
Boardman, Phillip C., Marcia Cohn Growdon, and Francis X. Hartigan, ed. Culture of the Middle Ages: A Festival of the Medieval Arts. Treasures of the Middle Ages. Reno, Nevada: Sierra Nevada Museum of Art, 1978. no. 45.
Castelnuovo-Tedesco, Lisbeth. "Romanesque Sculpture in North American Collections. XXIII. The Metropolitan Museum of Art. Part III: Italy (2)." Gesta 24, no. 4 (1985). no. 10, pp. 163-64, fig. 13.
Smith, Elizabeth Bradford, ed. Medieval Art in America: Patterns of Collecting, 1800–1940. University Park, Pa.: Palmer Museum of Art, Pennsylvania State University, 1996. p. 90.
Castelnuovo-Tedesco, Lisbeth, and Jack Soultanian. Italian Medieval Sculpture in The Metropolitan Museum of Art and The Cloisters. New York: The Metropolitan Museum of Art, 2010. no. 11, pp. 47–49.
Shalem, Avinoam. Die mittelalterlichen Olifante: Volume 1, Text. Die Elfenbeinskulpturen. Berlin: Deutscher Verlag für Kunstwissenschaft, 2014. p. 89 n. 188.