This mirror was used by John Dee to contact angels. For ten years, Dee and his scryer Edward Kelley received messages through the mirror. Dee believed the messengers were angels, Kelley thought they were demons, and begged to end the rituals...
Dee was a 15th-century scientist who, after a career of furthering academic thought and advising Queen Elisabeth the 1st, turned to the heavens in search of older wisdom. With the assistance of the scryer (and con man) Edward Kelley, Dee created a ‘Holy Table’ anchored by hermetic sigils, upon which this mirror acted as a portal to commune with other worlds. But John Dee was not the first person to use this mirror to speak with the other side. The mirror itself was made by the Aztecs of South America to communicate with a god called Tezcatlipoca—the harbinger of discord.
The mirror’s wooden case is covered in tooled leather. Sometime in the 17th-century, art historian Horace Walpole added a handwritten quote from Samuel Butler’s poem Hudibras:
Kelly did all his feats upon
The Devil’s Looking Glass, a stone;
Where playing with him at Bo-peep,
He solv'd all problems ne'er so deep
Reed Enger, "Obsidian Mirror," in Obelisk Art History, Published April 05, 2017; last modified October 31, 2022, http://www.arthistoryproject.com/artists/john-dee/obsidian-mirror/.