The first record of the ring’s use was on two letters of Clement IV in 1265 and 1266. It was used as a wax seal in private letters in place of the official lead seal used for solemn papal documents.

Intaglio is an ancient carving technique for adding ... as was the case with rings, used to stamp the wax seals of verified letters. [Nicolas Tranchant] works in the jewelry industry, and wondered ...

Part of this ritual involved the trio "validating" the seal, which you can see in the video below. You can see them testing to make sure the doors are locked and inspecting the seal. The wax was ...