The Festa delle Marie celebration dates back to the 10th century as an hommage to the purification of the Virgin Mary.
12 beautiful brides from amongst the poorest families were selected, blessed at the church of San Pietro in Castello and taken as brides to rich nobles young men.
It happened that during one of these events - probably 946 AD, but historians are still debating about the date - pirates from Dalmatia entered the church during the blessing and kidnapped the 12 brides and all their jewels.
Venetians reacted, followed the pirate ship, catched up with it at the port of Caorle, rescued the brides and "took proper care" of the pirates.
The girls were such rescued and returned to Venice and since that day the site has been known as the Porto delle Donzale (Port of the Ladies).
But the parade now was recognized as being so ostentatious of richness and power that at a certain point, in 1349, the "Marie" were substituted by wooden representations ... and it resulted in a very unpopular thing to do.
The parade was eventually stopped in 1793.