Jolly Roger 

The Jolly Roger is the flag that shows the Skull and Crossbones.  It is considered to be the flag of pirates.  It is also said the this was the flag flown on the maritime ships of the Knights Templar, after they were arrested, tortured and sometimes burned at the stake by both King Philip the Fair of France and Pope Clement V, the leader of the Catholic Church.

(See "The Templar Pirates" page 44)

It is said that the Skull and Crossbones on the Jolly Roger indicated that the Knights Templar believed that all that had to survive of the body to get to Heaven was the Skull and two bones.  This seems to have been at odds with the Catholic Church.