Gather around and I shall tell you a tale.

In the year of 1077, at Canossa, King Henry IV of Germany (1056-1106) submitted to Pope Gregory VII. The king sought pardon of the pope, and (as the legend goes) stood barefoot in the snow outside the papal quarters for three days. Some described this incident as the peak of medieval papal power. After that Henry IV arranged the election of an antipope. This struggle of power errupted into a war that lasted from 1077 until 1122, when they came to a compromise.

The legend of this struggle (the 3 days of waiting) is sometimes used in reference to similar stories in our time, such as concordats and other church related madness, which will always be around. It is not, however, a story commonly heared, and no one really knows of it.

Note: 1077 is also Fry's PIN number. Also the price of a cheese pizza and a large soda back where he used to work: Panucci's Pizza.

Sources:
http://www.temcat.com/kn4.htm
http://home.carolina.rr.com/wormold/germany/
http://www.fox.com/futurama/