2000 years old die from Egypt (with 20 sides)11:03 AM
Indeed, even the dice with simple letters might relate to divination: a Greek oracle book composed in in the 2nd or 3rd century AD refers to throwing lots to obtain a number that would, through certain algorithms, lead to ready-prepared oracle questions and responses.
For most of the world, the d20 probably didn’t become a household term until the 1970s when Gary Gygax and Dave Arneson unleashed their epic fantasy RPG, Dungeons & Dragons, on the world. Since then, the d20 System, as it came to be known, has been used in everything from Star Wars RPGs to Gamma World. Since then, the d20 has become a staple of the geek world, a must-have in anyone self-respecting nerd’s utility belt.