San Cassiano Altarpiece: Saint Nicholas of Bari (left fragment)

Saint Nicholas, the bishop of Myra whose bones were brought by sailors from Bari to southern Italy in 1087, is easy to recognise here. He holds a closed book with three golden balls resting on it, the three bags of gold he was said to have thrown secretly through a poor man's window so that the man's daughters could marry. Antonello paints him as a heavy, unsmiling old man in a stiff gold cope.

The young face in profile beside him is harder to name. The museum's own title for this piece speaks of a choirboy, while its record for the reconstructed altarpiece suggests Saint Anastasia, with a question mark, and other scholars have seen Mary Magdalene. The fragment, about 56 by 35 centimetres, comes from the lower left of the painting.