Fig. 1: Map of Belgium and the cities from which glass has been analysed. Archaeological, plain window glass was collected from Heist, Brugge, Raversijde, Antwerp, Mechelen and Namur. The excavated glass from Binche originated from a stained-glass window. Samples from still existing windows were collected in Antwerp, Lier, Heverlee, and Brussels. The number of analysed fragments is indicated.