Because the figure is dressed in imperial garb--including the loros wrapped around his body and a crown with pendilia, he is most likely the royal St. Constantine. Along with his mother St. Helena, also dressed in royal robes, these saints were often shown flanking a representation of the True Cross. Here, Constantine occupies the left wing of a triptych, indicated both by the direction of his gesture and the tilt of the head, as well as the rounded contour of the right edge of this plaque and the dowel holes in the right side of the top and bottom of the frame, allowing it to open and close. He was, in all likelihood, balanced on the right wing of the triptych by an image of St. Helena, who, in mediaeval tradition, had traveled to Jerusalem and discovered the True Cross. The exterior of the panel has a tall, slender cross balanced atop a complex podium containing a sequence of a trapezoidal, a circular, and a stepped section.
Constantine I, the Great, was the emperor who, through the Edict of Milan in 313, had extended toleration to Chrisitianity and promoted the worship of Christ through the many churches he had built in Rome and the Holy Land. His decision to move the empire's capital city from Rome to Byzantium, renamed Constantinopolls, had a profound and long-lasting effect on the cultural, religious, and political character of the medieval Roman Empire (known as the Byzantine Empire). It is perhaps for this reason that the saint's features resemble those of emperor's of the early and mid-10th century, about the time this ivory was carved. If the identity of the emperor was specificaly Constantine VII Porphyrogennetos, the resemblance creates a complex sign of authority and sanctity, aligning the living emperor with his imperial namesake.
Images of the Byzantine emperor were never straightforward portraits, but rather symbolic illustrations of the union of sacred and temporal power. In Byzantium, the gem-studded loros that criss-crosses the emperor's body was compared to both the cross of Christ and to the winding sheet in which he had been buried. The halo around the emperor's head head had emerged from a different realm of imagery: the pagan emperor's charisma, stressing the superhuman character of the ruler and his status.
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A. Goldschmidt and K. Weitzmann, Die byzantinischen Elfenbeinskulpturen des X.-XIII. Jahrhunderts, Vol. 2: Reliefs (Berlin, 1934; 2nd ed. 1979), 47, no. 75, pl. 29, 63.
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Walters Art Gallery, Early Christian and Byzantine Art, ed. D.E. Miner, exh. cat., Baltimore Museum of Art, April 25-June 22, 1947(Baltimore, 1947), 48, no. 148, pl. 29.
The Dumbarton Oaks Collection, Harvard University (Washington, D.C., 1955), 106, no. 233, fig. p. 118.
C. Diehl, Byzantium: Greatness and Decline, Rutgers Byzantine series (New Brunswick, N.J., 1957), fig. p. 252.
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K. Weitzmann, Catalogue of the Byzantine and Early Mediaeval Antiquities in the Dumbarton Oaks Collection, Vol. 3: Ivories and Steatites (Washington, D.C., 1972), 58-60, no. 25, pl. 36, colorpl. 5.
A. Cutler, The Craft of Ivory: Sources, Techniques, and Uses in the Mediterranean World, A.D. 200-1400 (Dumbarton Oaks, Byzantine Collection Publications, No. 8 (Washington, D.C., 1985), 16, fig. 30, 41, 46.
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———, "From Loot to Scholarship: Changing Modes in the Italian Response to Byzantine Artifacts, ca. 1250-1750," Dumbarton Oaks Papers 49 (1995): 237-67, esp. 258ff.
H. C. Evans and W. D. Wixom, The Glory of Byzantium: Art and Culture of the Middle Byzantine Era, A.D. 843-1261, exh. cat., The Metropolitan Museum of Art, March 11-July 6, 1997 (New York, 1997), 202-203, no. 139.
C. L. Connor, The Color of Ivory : Polychromy on Byzantine Ivories, (Princeton, 1998), 85, no. 44.
W. Noel, The Archimedes Palimpsest (Baltimore: Walters Art Museum, 1999), VHS, DVD.
G. Bühl, ed., Dumbarton Oaks: The Collections (Washington, D.C., 2008), 138, pl. p. 139.
C. Porphyrogenitus, The Book of Ceremonies: With the Greek Edition of the Corpus Scriptorum Historiae Byzantinae (Bonn, 1829), Byzantina Australiensia / Australian Association for Byzantine Studies, trans. A. Moffatt and M. Tall (Canberra, 2012), ii.
Baltimore, Baltimore Museum of Art, "Early Christian and Byzantine Art," April 25 - June 22, 1947.
Athens, Zappeion Exhibition Hall, "Byzantine Art, an European Art," Ninth Exhibition of the Council of Europe, April 1 - June 15, 1964, no. 90.
Washington, D.C., Dumbarton Oaks, "The Craft of Ivory," Oct. 22 1985 - Jan. 6, 1986.
New York, The Metropolitan Museum of Art, "The Glory of Byzantium: Art and Culture of the Middle Byzantine Era, A.D. 843 -1261," March 11 - July 6, 1997.
Washington, D.C., Dumbarton Oaks, "Cross References," March 25 - July 31, 2011.