The character of Stenterello was created around 1791 by Luigi Del Buono (1751-1832), and Stenterello was the name he received from the public, having the looks of a weakling.
Stenterello is the beloved mask of Florence, impersonating the character of Florentinians in those times.
One of the puns that were used for him: Posa Piano, meaning "take your time" but in a sickly way, of somebody being kind of slow.
The character of Stenterello (= barely grown) can be seen as:
He represents, in a way, the lower class Florentinian people, always oppressed, but at the same time still has the strenght to mock their situation and be happy.