Some historians trace the Jolly Roger flag to a system of communication used by pirates to trick and terrorize their sea victims. Early versions came with black or red backgrounds to communicate different levels of violent intent. Some also trace the flag to representations of pirates' identity and their sea experience.
One of the earliest uses of the term "Jolly Roger" applied to pirate flags is found in "The General History of Pyrates" from 1724. Though Charles Johnson has his name on the book, some believe Daniel Defoe is the author. Many think the origin of the term derives from the French phrase "Joli Rouge," referring to the red background of early flags. As Roger was at times a name for the devil, some think the name refers to the grinning, evil skull on the flag.
A main purpose of the flag was to terrorize and force submission of other ships, and early versions of the flag had the skeleton figure sending a sword through a heart while holding an hourglass. Early versions of the flag sometimes featured red backgrounds, which signaled to prey ships that the pirates would fight to the last person. The black background communicated that the pirates may give quarter, or mercy, to some individuals on the targeted ship.