The Mercuralia (May 15) honored Mercury as the patron god of merchants and the grain trade. A Roman merchant would do the proper rituals of devotion to Mercury and then beseech the god to remove from him and from his belongings the guilt coming from all the cheating he had done to his customers and suppliers.

Let the Buyer Beware!

Mercury's festival
Features a ritual
Tinged with deceit;
Swindle-prone merchants use
Fraudulent practices...
Get a receipt!