"
"
Hidden in secret, a message can be transcoded and embedded on the surface of an image where it looks like an artifact, or part of the image. Roͬͬ͠͠͡͠͠͠͠͠͠͠͠sͬͬ͠͠͠͠͠͠͠͠͠aͬͬ͠͠͠͠͠͠͠ Menkman/Flickr (CC BY 2.0)
And you thought
your tattoos were provocative. In the year 499 B.C.E., Histiaeus — a Greek adviser to the Persian King Darius I — ordered an enslaved person to visit his son-in-law, Aristagoras. When the man arrived, he asked that his head be shaved.
There, tattooed on the enslaved person's scalp, was a hidden message from Histiaeus. It told Aristagoras to instigate an uprising against none other than the Persian King himself, Darius I.