Francisco Gallego, St. Catherine Altarpiece: Detail, St. Catherine

On the left is the incident of the wheel; on the right, the beheading. The portrait in the center features St. Catherine's major attributes, the sword and wheel, but not the palm branch that is customary in portraits of martyrs. The saint's erudition is signified by the large book on her left arm and the small one on the false sill at left.

View this image in full resolution.
View the entire altarpiece.
Read more about St. Catherine of Alexandria.

Photographed at the site by Richard Stracke, shared under Attribution-NonCommercial-ShareAlike license.