The panels, depicting the Ancestors of Christ, have been re-dated using a new, non-destructive technique.</span>
The analysis indicates that some of them may date back to the mid-1100s.
The windows would therefore have been in place when the Archbishop of Canterbury, Thomas Becket, was killed at the cathedral in 1170.
Léonie Seliger, the head of stained glass conservation at the cathedral, and part of the research team, told BBC News that the discovery was historically "hugely significant".
"We have hardly anything left of the artistic legacy of that early building [apart from] a few bits of stone carving. But until now, we didn't think we had any stained glass. And it turns out that we do," she said.
Dr Laura Ware Adlington, who led the research, said that the windolyser's results were "very exciting".
"These findings will make us all, from art historians and scientists, to members of the public visiting the cathedral, look at the Canterbury stained glass in a whole new light."
Prof Caviness said she was ''delighted'' to hear that her assessment had been confirmed by Dr Ware Adlington.
''The scientific findings, the observations and the chronology of the cathedral itself all fit together very nicely now,'' she told BBC News. Prof Caviness, who is now 83, told me that the finding had jolted her out of a ''Covid numbness'' that she had been feeling.
''I wish I was younger and could throw myself more into helping Laura with her future work. But I've certainly got a few more projects to feed her.''
Dr Ware Adlington's study suggests that some of the Canterbury Ancestors may date back to the back to the period between 1130-1160, at least 10 years before Thomas Becket's infamous killing at the site in 1170.