Just a little googlelove to add to the discussion:
The most famous flags
flown by pirates to indicate they were such were all called the “Jolly Roger” and were adorned with a variety of artwork or often no art work
at all. Most of these flags were simply black or red with nothing on them. Historical accounts indicate that, should a pirate ship raise a black flag, it indicated that so long as the ship they were attacking surrendered with no resistance, they would be given quarter. Should anyone aboard the ship resist or should the ship try to flee once the black flag was raised, the black flag would be lowered and the red flag would be raised. This flag indicated that no mercy would be shown to anyone aboard the ship that was about to be attacked.
Records of pirate ships flying flags that signified they were pirates go back just about as far as history
is recorded. Of the Jolly Roger line though, the earliest reference is probably of the skull and crossbones flag used by the Knights Templar, who had the world’s biggest naval fleet in the 13 century and were well known for their pirate-like acts on the sea. When the Knights Templar dissolved, with many members forming the Knights of Malta
who were equally known for their piracy
, they also were known to fly the skull and crossbones.
The tradition to use the Jolly Rodger on submarines stems from 1901 when Admiral Sir Arthur Wilson VC said submarines were “underhand, unfair, and damned un-English. … treat all submarines as pirates in wartime … and hang all crews.” Upon learning
of this, Lieutenant Commander Max Horton, who later became an Admiral, raised the Jolly Rodger when his submarine was returning to port after sinking the German ships SMS Hela and the destroyer SMS S-116. Thus, the tradition was born that on the completion of a successful mission, the returning submarine should fly the Jolly Roger. This eventually spread into the Jolly Roger being the official emblem of the Royal Navy
Reference: Origins of the Jolly Roger