Many centuries before Dungeons & Dragons was even a glimmer in the eye of Gary Gygax, ancient Egyptians were rolling a d20 die.
Let's go back in time. Way back. Keep going. OK, stop. You're in the Ptolemaic Period. It's somewhere around 304 to 30 B.C. You're in Egypt. You're playing Dungeons & Dragons. Except back then, it's more like Pyramids & Petsuchos.
The Metropolitan Museum of Art owns what may be the world's oldest d20 die. It's made out of serpentine and looks to be in remarkably good shape for its age.
The die is a little over an inch tall. The symbols carved into the die appear to be of Greek origin, in keeping with it coming from the Ptolemaic Period.
The symbols for eta, theta, and epsilon can be clearly seen. Maybe it was used to determine which frat the ancients were going to pledge, but I'd like to think it was used to roll for hit points for warrior and sphinx classes. Now all we need is for someone to 3D-model this so we can print it out and make up our own ancient Egyptian version of D&D.