Who introduced the role that John Rich played from 1717 to 1760?
John Rich (producer):  He introduced pantomime to the English stage and played a dancing and mute Harlequin himself from 1717 to 1760 under the stage name of "Lun." Harlequin:  The role is traditionally believed to have been introduced by Zan Ganassa in the late 16th century, and was definitively popularized by the Italian actor Tristano Martinelli in Paris in 1584–1585 and became a stock character after Martinelli's death in 1630.
Zan Ganassa