Were there really maps centuries ago that on unexplored areas, said “Here there be monsters”? Or is that a myth? I have never seen such a map in picture books on the history of cartography.
Well, a google on “here be dragons” site:.edu turns up quite a few hits; it appears to be a well-documented idea that ancient maps did bear such inscriptions (apparently so that unexplored areas wouldn’t just be blanks on the page), but I’ve yet to find a specific example.
From one of my classics courses in college, I recall there being a connection between Ptolemy and such an inscription.
This is the only online source I was able to find that mentions the connection, but it’s not a very robust cite. (It’s an interesting article, though. )