And Dee’s sectarian allegiances, seemingly malleable depending on the denomination of whatever land he should happen to find himself in, was focused on a type of positivist magic. His was a counter-Renaissance, indebted not to Erasmus and More but rather Ficino and Mirandola. Not quite at home in the classical humanism of his fellow rhetoric-minded colleagues, Dee longed to create the English equivalent of the Neo-Platonist and hermetic academies which had thrived in Florence a century before. But his was an esoteric knowledge, even during an esoteric age. The great Warburg scholar Dame Frances Yates claimed that his massive library was the very mind of the Renaissance. A sixteenth-century magus, Dee straddled the now-seemingly contrary realms of the occult and science. John Dee has long fascinated students of the Renaissance. He affixed a label to the mirror which simply stated “The Black Stone into which Dr Dee used to call his spirits …” This particular mirror was owned by the eighteenth-century gothic writer, architect, and son of the former Prime Minister, Sir. Now, spirited away from a destroyed and subjugated civilization they journeyed to a profoundly different culture where they would create new stories, and generate new prophecies. The Aztecs had used obsidian stones just like this one for prophetic purposes over the course of generations. The conquering Spanish brought back things like this by the boatload while they plundered Aztec gold to become the world’s first truly global empire (and in the process they imported disease, war, and slavery). This is a ritual object, and its exact provenance is unknown. A beautiful, dark, reflective black, it was forged from volcanic Mexican obsidian which the Aztecs associated with their god Tezcatlipoca, lord of divination (among other things). Not much bigger than any standard hand mirror, the artifact is circular with a hole-bored handle at the top. In the British Museum – away from the Rosetta Stone and Elgin Marbles with their legions of selfie-taking tourists – is a shiny, jet-black obsidian mirror (Figure 1).