panels were actually fragments of the same picture. Zeri’s reconstruction
was generally accepted in the literature and later confirmed by X radiogra-
phy. It was not, however, until the planning stages of the Metropolitan
exhibition Painting in Renaissance Siena: 1420–1500,held in 1988 in honor of
John Pope-Hennessy’s seventy-fifth birthday, that a decision was made to
exhibit the pictures together.
The treatment ofthe panels evolved from the initial idea of minor
cleaning and corrective retouching for the purpose of exhibiting the pic-
tures side by side, to a major cleaning and structural intervention, which
ultimately included the reconfiguration of the Washington panel into a
lunette, the permanent rejoining ofthe two panels and, finally, joint own-
ership between the two museums.
The scope and objective of the intervention broadened several
times during the process because of the emergence of new information
that continually expanded the understanding of the work as a whole. New
physical evidence uncovered at various stages pointed toward the need for
increasingly extensive interventions that the conservators and curators
concluded were justified by the prospect of real aesthetic gain with the
least conjecture. At each step, intervention was limited to the minimum
necessary to achieve a clearly attainable goal, based on structural and
aesthetic integrity within the giv en context. As the context changed, the
permanent rejoining became a more and more logical alternative; and it
stands as a credit to the conservation, curatorial, and administrative staffsT N F G M 343Figure 2
Francesco di Giorgio Martini, God the Father
with Angels,1471–72. Tempera on panel,
36.5 3 51.8 cm. National Gallery of Art,
Washington, D.C.