The Italian Venetian masks first made an appearance in 1268 at the annual celebration commemorating the defeat of Ulrich II. Masks continued their popularity as Venice rose to become sort of the Vegas of it's day, with visitors seeking to protect their identity while indulging in some questionable behavior.
In the Renaissance period, these masquerade masks were adopted by the Commedia Dell Arte. They all but disappeared while Venice was under Austro-Hungarian rule, only to be resurrected in the 1970's by artists seeking to profit from the tourist trade. In the Americas, they are popular today for Carnival and Mardi Gras masquerade balls and celebrations.
Venetian masks consist of several recognizable styles, each with it's own name and distinct history. Some of the most popular are:
The Moretta - a black velvet mask covering the whole face, worn by ladies.
The Bauta - a heavily-gilded black or white mask covering the entire face.
The Larva or Volto - a shiny, white mask, often worn with a black cloak and a tricorn hat.
The Columbine - a half-mask, decorated in gold, rhinestones and/or feathers, held up to the face on a stick or tied with a ribbon.
Medico Della Peste or "The Plague Doctor". This mask, with it's long, beak-like nose, originates from a style that was actually used during the bubonic plague. The nose part was stuffed with vinegar-soaked sponges and various salts and disinfectant herbs, in an attempt to protect the wearer from the disease.
For more information about the Carnival of Venice and the traditional Venetian masquerade masks: