WEDNESDAY is derived from Old English Wodnesdæg and Middle English Wednesdei, "day of Wodanaz", ultimately a calque of dies Mercurii "day of Mercury". Within the ancient Roman pantheon he is the patron god of financial gain, commerce, eloquence (and thus poetry), messages/communication (including divination), travelers, boundaries, luck, trickery and thieves; he is also the guide of souls to the underworld.