The phrase “Here Be Dragons” actually appears only once on a historical map, on the early 16th century Hunt-Lenox Globe. And actual dragons live there.
Mapmakers sometimes drew foreign and mythological creatures in the blank spaces on maps, not so much as a warning but as a kind of marginalia or decoration. Nevertheless, the modern stereotype is that the dragons and other beasts on such maps – accompanied by the phrase “Here Be Dragons” – indicated the peril possible in the lands beyond those we know.
In the historical record, alas, this phrase doesn’t actually appear in maps that often. “Here Be Lions” was used by ancient Roman cartographers for the same purpose, but dragon? Much rarer. And by rarer, I mean that it appears exactly once.
HC SVNT DRACONES
That’s the Latin for “Here Be Dragons,” and it appears on the Hunt-Lenox Globe. Dated at somewhere around 1510 CE, it’s one of the oldest globe maps in existence, and one of the first to contain the Americas… even if it’s a completely incomplete and inaccurate outline of the Americas.
The phrase appears off the Eastern coast of Asia, fairly close to modern-day Indonesia. Which, of course, is the one place on Earth that actually has dragons (Komodo dragons, to be precise). So the only historical usage of this phrase is also, incredibly, actually pretty accurate.
[Thanks to Gareth E. for suggesting this topic.]