In Greek mythology, Charon was the ferryman who conveyed souls across the river styx that divided the world of the living from the world of the dead. Ancient Greek and Latin literary sources specify a coin as a payment or bribe for Charon. This payment was called an obol. According to legend, Charon’s obol was placed in or on the mouth of a dead person before burial.
In Latin, Charon’s obol was sometimes called a viaticum, or “sustenance for the journey”; the placement of the coin on the mouth has also been explained as a seal to protect the soul of the deceased or to prevent it from returning.