De Crayer produced this oil sketch in preparation for a commission he received to paint the altarpiece for St Catherine’s Church in Brussels. In the final composition, he reversed the arrangement of the figures. Saint Catherine of Alexandra was one of the great Christian martyrs. Her opposition to the tyrannical rule of the pagan Emperor Maxentius sealed her fate, and she was subsequently put to death on a spiked wheel. Part of that wheel is just visible beneath the saint’s left knee in this oil sketch. Catherine is also famous for her chastity, and was believed to have had a vision in which she was mystically betrothed to Christ. Images of Catherine (and of this episode in particular) abound in western art, especially from the Renaissance and early modern period.