The "bullo" is in Italian, what can be translated by "bully".
But it's not quite the case here.
It may mean something more like "show-off" as the masked guy pretends to have done such courageous acts, fighting around.
"Masch: da Bullo che va narrando
le bravure, ch'a fatto in Italia"
"Mask of a bully that is talking about
all the brave acts he has done in Italy"
It is interesting to see here how the idea of "Italia" is presented as some sort of a foreign land, as it was in those times.
We are with all probability talking about the XVI-XVII century.
In another printing of the same image, there is a different text presented, that gives a little more information about his story:
"In Italia son io chiamato il bulo
Perche dí ferro hò, petto, schena, e culo."
"In Italy I am called the bully
Because of iron I have chest, back, and buttocks
."
