Harlequinades evolved from the Italian genre of "street theatre", known as comedia dell 'arte. These plays involved physical comedy and pantomime, and featured a cast of stock characters, each with specific movement patterns used to convey their personalities.
This style of theatre first appeared in England in the 17th century. The 18th century pantomime became a prominent theatre genre, with John Rich, the manager at Lincoln's Inn Fields in London, often being cited as the father of English pantomime. Under Rich the structure of English harlequinades took shape. With the main characters of Harlequin, Columbine, and Pantaloon at the helm, pantomimes were separated into two parts: the first scene introduced the narrative, often based on a classical tale transitioned (via magical transformation and spectacle) into the second scene featuring the aforementioned stock characters and focusing on the 'star crossed' love affair of Harlequin and Columbine.
Using these stock characters and narrative structure, harlequinades could be set in any place or time period. Harlequin was considered the star of the pantomime until the debut of Joseph Grimaldi in the early 19th century. Grimaldi was exalted for his performances in pantomimes as Clown, a character who gained prominence in the genre at the end of the 18th century, and emphasized the topical satirical potential of the genre. Harlequinades continued to be performed after Girmaldi's death in 1837, but changed in structure to include "music hall performers" and elements towards the end of the 19th century. Pantomimes continue to be performed despite many elements of the early harlequinade being lost.
Victoria and Albert Museum, "Early Pantomime," 2016, http://www.vam.ac.uk/content/articles/e/early-pantomime/.
Mayer, David III. Harlequin in His Element: The English Pantomime, 1806-36. Cambridge: Harvard University Press, 1969.
Broadbent, R.J. A History of Pantomime. New York: Benjamin Blom, Inc, 1901.