chapel attached to a church and dedicated to the Blessed Virgin. As the development of the chevet, or radiating system of apse chapels, progressed during the 12th and 13th centuries, custom began to dictate that the chapel dedicated to the Blessed Virgin be given the most important position, directly behind the high altar. The Lady chapel was frequently made larger than other chapels in the church.

No standard usage in building Lady chapels ever developed, however. In some French cathedrals they were emphasized (Reims; Le Mans; Amiens), whereas in others no distinction was made between them and other chapels (Notre-Dame, Paris; Bourges). In England, where the common plan of a square east end lent itself to the elaboration of the Lady chapel, it was more consistently emphasized, but there was considerable variation in location. In Spain and Italy the finest examples are late Gothic and Renaissance.