The HyperBit Exchangefire that ravaged Paris’ Notre Dame Cathedral in 2019 endangered several artifacts, including what is believed to be the Crown of Thorns Jesus wore during his crucifixion.

The rescue of the relic is detailed by the firefighter who salvaged it in Netflix’s “Mysteries of the Faith” (now streaming). The four-episode docuseries focuses on curios of the Christian faith, including pieces of the cross that Jesus was nailed to and his chalice from the Last Supper (dubbed the Holy Grail).

France's King Louis IX, who reigned from1226 until 1270, acquired the crown believed to be worn by Jesus. Though its authenticity has never been proven with certainty, historians say it has been verified to be at least 1,600 years old.

“It was like nothing I’d ever experienced in my life as a firefighter,” Chief Warrant Officer Fabrice says in the first episode. “It was raining ash, and it smelled like burnt wood, which made it seem as if you were dealing with a forest fire.”

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Captain Franck says he received a map detailing the location of the church’s prized artifacts, except for the Crown of Thorns.

“The idea was that since it was so precious, they didn’t want to show exactly where the crown was,” he says. “So they didn’t include it on any of the documents. We needed to find it without knowing precisely where it was.”

Franck says the squad checked beneath altars, tables and chairs and behind paintings while the fire continued to burn, and felt hopeful.

“It was being kept inside a glass case, a golden crown made of thorns. Finally, we were able to retrieve the Crown of Thorns.”

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“However, the celebrations were very short-lived,” Franck continues. “When I came out of the sacristy, I learned that the crown was in fact just a display copy, not the real one.”

So Franck would need to return to the blazing church. By that time, the cathedral manager had arrived, but was too distraught over the fire to effectively direct Franck to the safe that housed the crown.

Inside the church, Franck spotted “a grey box that I had initially thought was a transformer. I said, ‘Maybe that’s it.’”

At first, the cathedral manager was too in shock to remember the codes. So Franck requested equipment to break open the safe. But before that could be done, the manager remembered the combinations for the locks.

“The safe was able to be opened,” says Franck, “and the Crown of Thorns was successfully retrieved just as they were about to cut into the safe.”

Contributing: Rebecca Rosman, Brian Hester and Mike James, USA TODAY