Relatively little is known about stained glass windows in England predating c. 1170; however, art-historical evaluation by Caviness (1987) argued that four figures from the “Ancestors series” of Canterbury Cathedral, usually dated to the late 12th and early 13th century, in fact date earlier (c. 1130–1160). This would place them amongst the earliest stained glass in England, and the world. Building on our previous work, we address Caviness’s hypothesis using a methodology based upon analysis of a few, well-measured heavy trace elements and a 3D-printed attachment for a pXRF spectrometer that facilitates in situ analysis. The results confirm two major periods of “recycling” or re-using medieval glass. The first is consistent with Caviness’s argument that figures predating the 1174 fire were reused in the early 13th century. The results suggest that in addition to figures, ornamental borders were reused, indicating the presence of more early glass than previously thought. In the second period of recycling (1790s), surviving figures from the Ancestors series were removed and adapted into rectangular panels for insertion into large Perpendicular-style windows elsewhere in the cathedral. The results show that the glasses used to adapt the panels to a rectangular shape were broadly contemporary with the glasses used to glaze the original Ancestors windows, again representing a more extensive presence of medieval glass in the windows