Most often, the provenance of a skull is unknown. Those from the collection of the Mütter Museum (where I photographed this image) are unusual in that they were carefully documented. While any skull is a universally understood memento mori (appearing in everything from classical still life and vanitas painting to present-day poison warnings), knowing the specific history deepens the experience of contemplating one. This particular skull — of one who killed, and was then himself killed as punishment — felt especially layered and appropriate to the theme of end of life.