At present, one window has been taken off display. This comprises the “Life of Christ and the Virgin” consisting of three lights, and a single panel, “Siegfried von Gelnhausen and his wife”.
This stained glass was purchased by Sir William Burrell from the collection of the bankrupt William Randolph Hearst. The “Life of Christ and the Virgin” was made around 1440 to 1446 for the Carmelite church at Boppard-am-Rhein (just south of Cologne). It was part of seven enormous windows each in praise of the Virgin Mary.
Siegfried von Gelnhausen and his wife were the donors of another window at the church, the “Life of Christ Tree”, now in California.
Lots more information to come, but if you have questions or comments, please fire away!