The genealogy of the whole family is confirmed by the general term which includes them all:  in English, Zany; in Italian, Zanni; in the Latin, Sannio; and a passage in “Cicero De Oratore,” paints Harlequin and his brother gesticulators after the life; the perpetual trembling motion of their limbs, their ludicrous and flexible gestures, and all the mimicry of their faces:  “Quid enim potest tam ridiculum quam Sannio esse?  Qui ore vultu, imitandis motibus, voce, denique corpore ridetur ipso.” Lib II., Sect. 51. ("For what has more of the ludicrous than Sannio?  Who, with his mouth, his face, imitating every motion with his voice, and, indeed, with all his body, provokes laughter.”)

The Latin Sannio was changed by the Italians into (as Ainsworth explains) Zanni, as, in words like Smyrna and Sambuco, they change the s into z, which gives Zmyrna and Zambuco, and hence we derive our word Zany.  The word is, however, originally obtained from the Greek Sannos (observes Quadrio), from whence the Latins derived their Sannio.

From the size of the ancient theatres it was not possible to notice the visage of the actors, and this was one, but not the only reason, why masks were adopted.  The Ancients did not like a character to be attempted, to which a proper appropriation was not annexed, and these masks were so contrived, that the profile on one side exhibited chagrin, and on the other serenity, or whatever other passion was most required.  The actor thus, according to the part he was playing, presented the side of the mask best suited to the passage which he was reciting.  The large mouths of these masks were presumed to have contained some bronze instrument suited to assist the voice, upon the principle of the speaking trumpet; for the mask was wider, and the recitation in tragedy much louder than in comedy, so that the voice might be heard all over the theatre.  The masks of the dancers were of regular features.

By some it has been contended that these masks covered both the head and the shoulders under the supposed idea that when the head was thus enlarged it would throw the whole body into symmetry when raised upon stilts.  It has, also, been argued that the masks for some of the characters were made of gold-beaters skin, or some transparent substance just covering the face so that the facial muscles could be seen through it, and the eyes, mouth, and ears being left uncovered.  These masks, however, delineated very carefully the features of the character that were to be represented.  Something not unlike the huge Pantomime masks of a hideous and frightful shape that we sometimes see in our present day Pantomimes must have appeared, especially those that covered the head and shoulders of the Mimis in the days of the Romans.  Those that were just of the size of the face in all probability were fantastic and picturesque; and the third and remaining species of mask made of a transparent substance could hardly have been very effective.