Pieter Coecke van Aelst and his workshop were involved in the design of stained glass windows for the former abbey church of Herkenrode, one of the wealthiest in the Low Countries and the former Principality of Liège until the suppression of the religious com- munity and the sale of the abbey at the end of the eighteenth century. These windows, much rearranged, are now displayed in Lichfield Cathedral in England. They have just been systematically studied on the occasion of their restauration by the Barley Studio. These are key works for understanding the process of artistic invention in the former Low Countries at the beginning of the sixteenth century. These windows are rooted in the tradition of stained glass, but their subjects are brilliantly adapted from drawings to the requirements of the monumental scale and material constraints of the new medium. They reflect other recent artistic activity as well, including the weaving in Brussels of tapestries after cartoons of Raphaël and his collaborators, and the works in progress in the Galerie François Ier at Fontainebleau.