Saint Catherine of Siena Intercedes with Christ to Release the Dying Sister Palmerina from Her Pact with the Devil

The left side shows Saint Catherine of Siena in a white habit with a black mantle, raised hands in intercession, while red-winged angels hover behind her and a horned, bat-winged demon advances from a doorway clutching a scroll of writing. To the right, Sister Palmerina lies ill in a bed within a gray architectural chamber, as a nun and a laywoman stand nearby and a priest with another nun consult a lit book, with a red-clad figure seated at the bed’s edge. The composition uses a tripartite, narrative layout, with bright primary colors, strong outlines, and a relatively flattened space typical of Italian late medieval to early Renaissance altarpieces.