Shell cameos are much easier to cut than those made from gemstones. Also, the raw material is cheaper and easier to acquire. They were popular in the 16th century and then again in the 18th and 19th centuries, when the passion for carved gemstones led to a parallel explosion in the market for cheaper shell cameos. They are still popular today. In Greek mythology, Hercules was a heroic figure who personified strength and courage. As a penance for killing his own children in a rage, he had to perform the Twelve Labours. Here he is shown resting, holding aloft his club and wearing the skin of a lion, his two main attributes.