Harlequin, or Arlecchino (Italian), is the most popular of the 'zanni' or comic servant characters from the Italian "Commedia dell'arte" and it's descendant, the "Harliquinade".

The name of Harlequin derives from Old French Hellequin, leader of la maisnie Hellequin, thought to be related to the Old English Herla, a character often identified with Woden.

Italian Arlecchino by folk etymology was associated with Latin Herculinus, "Little Hercules".
Although illustrations of Archellino have only been dated as far back as 1572, the character had existed before this date. The origins of the name are uncertain: some say it comes from Dante's Inferno, XXI, XXII and XXIII; one of the devils in Hell having the name Alichino.

Popular theories suggest that he may have come from France, Africa, or Italy.

The notion that the Harlequin motif grew out of France is evidenced by Hellquin, a stock character in French passion plays. Hellequin, a black-faced emissary of the devil, is said to have roamed the countryside with a group of demons chasing the damned souls of evil people to Hell. The physical appearance of Hellequin offers an explanation for the traditional colours of Harlequin's mask (red and black).

[ from Wikipedia.org, "Arlecchino"]

Arlecchino, oder Die Fenster (Harlequin, or The Windows) is a one-act opera with spoken dialogue by Ferruccio Busoni, with a libretto in German written by the composer in 1913. He completed the music for the opera while living in Zurich in 1916. It is a number opera written in neo-classical style and includes ironic allusions to operatic conventions and situations typical of the late 18th and early 19th centuries. It even includes a parody of a duel.

The opera is unusual in that the title role of Arlecchino is primarily a speaking role. Arlecchino and the other roles in the opera are derived from the Italian Commedia dell'arte.

[from Wikipedia.org, "Arlecchino" the opera]