Guising refers to the Scottish and northern English tradition of disguising oneself in costumes, often with masks, and visiting people's homes around Halloween. This practice has its origins in medieval traditions where people would go door-to-door performing plays in exchange for food or drink. The modern practice of trick-or-treating on Halloween may have developed from the belief that spirits roamed the earth on this night and needed to be appeased with food or gifts. Records show guising was practiced in Scotland in the 16th century and other parts of Britain and Ireland in the late 18th and 19th centuries, with people singing songs or reciting verses in exchange for food, money, or other treats.