The characters were always identifiable by their masks and costumes. In commedia dell'arte, "mask" referred not literally to a face covering but to a particular character type. Other familiar commedia dell'arte characters are Harlequin and Columbine (comic servants), Pulcinella (a vicious character who was the forerunner of the Punch character in Punch and Judy), and Scaramouche (an adventurer).
In the beginning, the Pierrot character was a side-show act that was a prelude to the actual performance. Pierrot was a tumbler and acrobat who performed imitations and caricatures. The Pierrot character was a "zanni," or clown, who enjoyed playing pranks and whose job it was to cause confusion in the play. He dressed all in white (sometimes with black accents). His hat was either tall and pointed or sometimes small and brimmed.
Pedrolino or Pierrot was often made up with a powdered white face, more rarely an actual mask. The actor portraying Pierrot was traditionally expected to show a great range of emotions on his face. Pierrot portrayed a charming and kind person who was so trusting that others took advantage of his naiveté. He was a "born loser" who became the sad clown when his heart was broken by Columbine, who loved Harlequin instead.
The transformation of the Italian character Pedrolino into his French counterpart Pierrot is attributed to an actor named Giuseppe Giratoni who played in the Parisian company in about 1665. He accentuated the character's innocence and dressed in the outfit that we associate with Pierrot today--a baggy white costume with long sleeves and a ruff, with a large hat that flopped around his whitened face.
By the late 19th and early 20th century, Pierrot had evolved into a "melancholy dreamer," a romantic with the temperament of the tormented artist. He was a stoic who hid his pain from others, except for perhaps a single teardrop on his face. Picasso's famous Cubist painting "The Three Musicians" featured two commedia dell'arte characters, Harlequin and Pierrot, along with a monk.