These plays were almost always performed in the winter or spring - at Christmas, on Plough Monday or at Easter. Throughout the period when the old year dies and is reborn, just as characters in the play die and are reborn. It is easy to see how the Victorians thought this was the remnant of some pre-Christian fertility rite. Maybe they were right. The truth is that no one knows the origins of this ancient custom.
Nor do we know why the players hid their faces. This was done by blackening the face, or hiding it behind strips of cloth or paper. Sometimes these "tatters" were also used to provide costumes, in other places old clothes would be used to make costumes suitable for each character.
Mummers plays fall largely into two types. The most common is the hero-combat play which the Herga Mumemrs perform, where a hero, representing good, fight an evil enemy. Less common are the wooing plays where a ploughman attempts to win the love of a fair lady.
The hero-combat plays vary remarkably little across the country. The names of the characters change but the plot and many of the words remain almost identical. Typically the good Saint George fights an evil saracen, or rather has someone do it for him. When the king's champion is killed he has to be revived by a quack doctor and Saint George has to finish the job himself. Of course Good always wins.
In 1898 the Harrow Observer noted that the mummers would "live on for centuries" but within 25 years they were forgotten. However, these plays cannot die - rebirth is part of them. From the surviving records of the Middlesex plays this old tradition has been revived.