Is there a Greek counterpart for the Roman god Janus?
Not really: “The Romans associated Janus with the Etruscan deity Ani. However, he was one of the few Roman gods who had no ready-made counterpart, or analogous mythology. We can find in Greece Janus-like heads of gods related to Hermes, perhaps forming a compound god: Hermathena (a herm of Athena), Hermares, Hermaphroditus, Hermanubis, Hermalcibiades, and so on. In the case of these compounds it is disputed whether they indicated a herm with the head of Athena, or with a Janus-like head of both Hermes and Athena, or a figure compounded from both deities.” Source: http://en.wikipedia.org/wiki/Janus_%28mythology%29 “Janus did not have a counterpart in Greek mythology.” Source: http://www.loggia.com/myth/janus.