on a paper covering most of the wooden back, a description in Italian and Latin concerned chiefly with the iconography (see object file in NGA Curatorial Records for transcription and translation)
Reportedly Trivulzio collection, Milan; (Count Alessandro Contini-Bonacossi, Florence); sold by 1937 or 1939 to Samuel H. Kress, New York; gift 27 February 1950 to the Samuel H. Kress Foundation, New York; gift 1961 to NGA.
- Distelberger, Rudolf, Alison Luchs, Philippe Verdier, and Timonthy H. Wilson. Western Decorative Arts, Part I: Medieval, Renaissance, and Historicizing Styles including Metalwork, Enamels, and Ceramics. The Collections of the National Gallery of Art Systematic Catalogue. Washington, D.C., 1993: 33-35, repro. 34.
The object is in worn condition, with losses to the enamel at all four corners, below the ox on the lower right, beneath the right arm of Christ, and at the top center. The lower corners of the metal plaque are broken off, but the corners of the wood backing show no corresponding damage, indicating that the wood postdates the damage. The wood is chipped at the edges and has holes, possibly wormholes, in many places. A triangular metal plate, surmounted by a ring for suspension, is affixed to the back. Of the nails that once held the metal plaque to the wood backing, only the corner ones remain.
Traces of gilding survive, notably around the figures' necks, in the lines surrounding the inner rainbow, the stool, and the cruciform rosettes, and in dots within the mandorla. The right arm of Christ is a replacement, with considerable damage to the enamel around it. X-ray fluorescence analysis, however, indicates that the alloy is similar to the rest of the body. This alloy is fairly pure copper, with traces of lead, silver, antimony, tin, iron, calcium, and chlorine (the last three elements probably present in corrosion products), consistent with medieval production. Gold and mercury in gilded areas indicate the use of fire gilding.
 Reports of 6 January and 4 February 1987, in NGA conservation laboratory files.