@leecatlee wikipedia says:
"The first documented sources mentioning the use of masks in Venice can be found as far back as the 13th century. The Great Council made it a crime to throw scented eggs. The document decrees that masked persons were forbidden to gamble.
Another law in 1339 forbade Venetians from wearing vulgar disguises and visiting nun's convents while masked. The law also prohibits painting one's face, or wearing false beards or wigs.
Near the end of the Republic, the wearing of the masks in daily life was severely restricted. By the 18th century, it was limited only to about three months from December 26. The masks were traditionally worn with decorative beads matching in color."