Portrait of Vittoria della Rovere as Saint Margaret

Painting on copper was an Antwerp speciality, and Sustermans had learned his trade in Antwerp before the Medici called him south. This portrait is on a copper plate 29.5 centimetres high, small enough to hold in one hand. The metal takes paint with no weave showing through, so the surface carries detail at the scale of a miniature and keeps a hard gloss that canvas will not give. Vittoria della Rovere, grand duchess of Tuscany, sat for it in the guise of Saint Margaret in her late teens, somewhere between 1639 and 1642. For most of its life the plate was not on show anywhere. It stayed in the Medici Guardaroba, the grand-ducal household store, and passed to the Uffizi only in 1773. The drawing Sustermans made for it is still in the Uffizi's cabinet of drawings.