(Christopher). A keeper of bears and a tinker, son of a pedlar, and a sad, drunken sot. In the Induction of Shakespeare's comedy called Taming of the Shrew, he is found dead drunk by a lord, who commands his servants to put him to bed, and on his waking to attend upon him like a lord, to see if they can bamboozle him into the belief that he is a great man, and not Christopher Sly at all. The “commonty” of Taming of the Shrew is performed for his delectation. The trick was played by the Caliph Haroun Alraschid on Abou Hassan, the rich merchant, in the tale called The Sleeper Awakened (Arabian Nights), and by Philippe the Good, Duke of Burgundy, on his marriage with Eleanor, as given in Burton's Anatomy of Melancholy (pt. ii. sec. 2, num. 4).
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894