They needed a god of trade. From his throne on Olympus, Zeus surveyed his family. He did not have to ponder long. Hermes was the god for the job.
Zeus gave him sandals with little gold wings and put him in charge of promoting the exchange of goods, the signing of treaties, and the safeguarding of free trade.
Hermes, who would become Mercury in rome, was chosen because he was the best liar.
(Mirrors - Eduardo Mendoza)