The skull and crossed femurs, or thighbones, is an image that dates to antiquity and functioned as a memento mori, a reminder that everything that lives must die. The symbol was used by several fraternal groups as a sober reminder of the importance of leading a moral life. It was also part of the Odd Fellows ritual of rebirth. As one Odd Fellows monitor noted, it was the symbol “perhaps…used most frequently, in both sacred and profane mysteries, as a means of impressing the mind with a realizing sense of the seriousness of the end of life.” One regalia catalog listed plaques similar to this one as “emblems to hang in lodge room” that were sold as one piece in a set of sixteen or eighteen emblems.

The skull and crossbones appears frequently in Masonic contexts as well. It serves as a focal point in a “chamber of reflection,” an anteroom outfitted with arcane symbols intended to encourage deep self-contemplation before a candidate begins his degree.