<P> The Knights Templar organisation, active from the 12th century until their demise in 1307, adopted a skull - and - crossbones flag to identify ships belonging to their vast fleet . The skull and crossbones as a pirate's flag could well predate the Knights Templar </P> <P> The symbol came to be used to mark the entrances of many graveyards, 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 </P> <P> The skull and bones are often used in military insignia, e.g. in coats of arms of some military regiments . </P> <P> In 1829, New York State required the labeling of all containers of poisonous substances . 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 . </P>

An octagon frame with the skull and crossed bones symbol denotes