The Roman god Mercury, a portion of the tapestry "Atlas Supporting the Armillary Sphere," ca. 1530, by George Wezeler, Brussels, Belgium. For the full tapestry, see image no. BS4748. Mercury was a messenger who wore winged sandals and a god of trade, thieves, and travel, the son of Maia Maiestas and Jupiter in Roman mythology. His characteristics and mythology were borrowed from the analogous Greek god, Hermes. Mercury has influenced the name of many things in a variety of scientific fields, such as the planet Mercury, and the element mercury. The word mercurial is commonly used to refer to something or someone erratic, volatile or unstable, derived from Mercury's swift flights from place to place. He is often depicted holding the Caduceus in his left hand.