Abstract:
Pliny the Elder’s Natural History which he seems to have completed shortly before his
death in AD79, preserves a story of how the emperor Nero used to watch the gladiatorial games in Rome with the assistance of a piece of a mineral which he describes as smaragdus (NH 37,64 ). This allegation is one of the most famous anecdotes within Pliny's text, and is routinely cited by various modern historians of science and technology. Pliny uses the term smaragdus to describe a wide variety of green minerals. The fact that Pliny describes this use immediately following his description of how smaragdi reflect objects in the same way as mirrors, ought to make it clear that he intended this anecdote as an example of the way in which smaragdus could be used as a mirror.
Pliny's claim is best explained as the result of the misreading and mistaken translation of a source which had originally described how Nero had used to watch the games like a spy, not in the manner of a man with a mirror.
