The Carnival in Venice is said to have originated from an important victory of the "Repubblica della Serenissima" (how it was called the town of VENEZIA in those times), in the war against Ulrich II von Treven, Patriarch of Aquileia, in the year 1162.
Ulrich II had to pay - to be freed with his soldiers, about 700 men - one bull and twelve pigs, and had to promise (which he certainly did) to do this every year, for the Giovedì Grasso feasting in Venice.
As a consequence, to celebrate this big victory, dances and reunions started to take place in San Marco Square.
Of course, how it was usual in those times, and due to the multicultural character of Venice, magicians and other despicable characters joined the fun. Some for business, some for fun only.
We should not forget that at the time, Venice was a rather powerful republic, center of much traveling inside Italy and on the road to China.
In the beginning the Carnival celebration started the day after Christmas and the tradition went on for several centuries until the XVIII century came, and was a rejoicing in music, culture, rich garments and a growing middle class.
The Venice Carnival was outlawed entirely in 1797 by Francis II Emperor of Austria, and it has been revived in 1979.
And this is more the Carnival we know, to which we relate more. The music of Vivaldi, the masks, the beautiful and mysterious women, craziness and treason, all together.