Rachel Koopmans examines the panels, which were thought to have been Victorian

For decades two panels in the medieval stained glass Miracle Windows at Canterbury Cathedral have been assumed to be replacements by Victorian restorers.

A detailed study in the Trinity Chapel now shows that they were installed in the late 12th century, making them the earliest known artworks depicting pilgrims travelling to Canterbury. An analysis proved that they date to the 1180s, within 20 years of Thomas à Becket’s death and 200 years before Chaucer wrote The Canterbury Tales.

Rachel Koopmans, a researcher from York University in Toronto, said that the last catalogue of the windows in 1981 said the panels were the work of a Victorian glazier, Samuel Caldwell.

Suspicions that they were older emerged last year because they can be seen in a