Was not this because kneeling was the agreed sign of sorrow and personal contrition, which was not to be introduced into the public worship on the great day and the solemn seasons of the Church's joy and thanksgiving?

If the kneeling Sposa be St. Catherine of Siena, the nun, and not St. Catherine of Alexandria, or if the two are introduced, then we may be sure that the picture was painted for a nunnery of the Dominican order.