Hermes / Mercury

As shining, slippery, and mercurial as the liquid metal to which he gave his (Roman) name, Hermes was the messenger of the gods.  Flying between Olympus and earth on the wings of his broad-brimmed hat and sandals, and carrying his snake-entwined herald's rod (the caduceus), he took messages to mortals from his father, Zeus. Sometimes he brought help, as when he showed Odysseus the magic herb that saved him from Circe's enchantment.

Other times he brought stern divine commands, as when he told Aeneas to leave Dido and establish the future site of Rome. Talker, trader, traveler, trickster, and thief, Hermes presided over all forms of exchange and communication.  His skill with words made him the patron of writers and orators, of academics and diplomats.

He saw to the circulation of goods by merchants and thieves (not that dissimilar, in the ancient Greeks' view), and watched over travelers and border crossers. As he himself crossed the boundary between heaven and earth, he also crossed the one between life and death. As psychopomp, or spirit guide, he conducted the souls of the dead to Hades-and, very occasionally, back again. In the Hellenistic period Hermes became associated with wisdom, hence the term "hermeneutics": the study of the principles of interpretation.

 by Geoffrey Miles, 30 Second Mythology