Skull and crossbones (symbol)

The skull-and-crossbone symbol depicts the typical arrangement of skulls and humeri in ossuaries, as in the example above from Sedlec (Czech Republic).

The symbol is an ancient one, becoming widespread with the medieval Danse Macabre symbolism. From at least the 12th century, it has been used for military flags or insignia and as a warning of the ferocity of the unit displaying it. It became associated with piracy from the 14th century onwards, possibly even earlier. By the 15th century, the symbol had developed into its familiar form.

The symbol came to be used to mark the entrances of many graveyards,[2] particularly Spanish cemeteries and also as an easily identifiable warning on poison and other dangerous liquid and powder containers since the 19th century. The skull and crossbones were also popular on crucifixes made in Northern Europe during the 18th and 19th century, worn on rosaries or as larger wall hangings in religious orders Memento Mori and symbolising Christ's victory over death. These crucifixes were also placed on coffins during a funeral and then later given to the deceased's family [3]

The skull and bones are often used in military insignia, e.g. in coats of arms of some military regiments.

In 1829, New York State required the labeling of all containers of poisonous substances.[4] The skull and crossbones symbol appears to have been used for that purpose since the 1850s. Previously a variety of motifs had been used, including the Danish "+ + +" and drawings of skeletons.

In the 1870s poison manufacturers around the world began using bright cobalt bottles with a variety of raised bumps and designs (to enable easy recognition in the dark) to indicate poison, but by the 1880s the skull and cross bones had become ubiquitous, and the brightly coloured bottles lost their association.

As the skull-and-crossbones symbol has also entered popular culture in the context of piracy and is undoubtedly its most well known icon, and since cartoonish pirates have become popular characters with children, there have been concerns that the "poison" symbol might have the effect of attracting the curiosity of small children familiar with "pirates" as depicted as a toy or play theme. For this reason, in the United States there has been a proposal to replace the skull and crossbones by the "Mr. Yuk" symbol. However, Mr. Yuk and his graphic rendering are registered trademarks and service marks of his creator, the UPMC Children's Hospital of Pittsburgh, and the rendering itself is additionally protected by copyright. This means that the name and graphic image cannot be used without a license from the owner—unlike the Skull and crossbones, which is in the public domain.

• Ossuary
• Danse Macabre
• Hazard symbol
• Human skull symbolism
• Jolly Roger
• Mr. Yuk
• Totenkopf