this series was thought to have been made on the 13th century. but researchers discovered that some of the panels, including this one of the prophet nathan, were made much earlier. it's only come to light now because of this device, called a windolyser. it may not look like much, but it was developed by scientists to be used on location without damaging the glass. it shines a beam onto the surface, which causes material inside to radiate. this radiation contains a chemicalfingerprint from which the researchers worked out their age. we've been working on this detective storing for some time, putting all the pieces in place, and then we finally get an answer, something new that brings together science and art into one story. it's fantastic. these are all stories that were recorded at the time they happened here. the discovery astonished leonie seliger, who looks after the stained glass windows here.