On the day of Sensa (Ascension) the historic "Marriage of the sea" is celebrated, in memory of the conquest of Dalmatia by Venetian ships headed by the doge Pietro Orseolo II in 999. This feast is a thousand years old; it is one of the oldest Venetian festivals.
It represented an important conquest because with it Venice freed the Upper Adriatic from piracy by starting to be the queen of this sea.
It was immediately decreed that every year, on the day of Sensa, the Doge and the bishop should go out of the Lido harbor to bless the water. Later, in 1177, Pope Alexander III gave the Doge Sebastiano Ziani a gold ring in gratitude for the help he had in reconciling the emperor Federico Barbarossa, recognizing the sovereignty of the sea over the Serenissima. From that moment on, the centuries-old tradition of the "Marriage of the sea" began, the mystical union of Venice with the sea.
The party was great. The Doge climbed amid trumpet blasts on his representative ship, the Bucintoro, with all his followers, the clergy, any foreign ambassadors present, the heads of the Council of Ten and other authorities. His personal banner was waving on the Bucintoro flagpole, while the same Admiral of the Arsenale gave orders. Followed by a large procession of boats of all shapes and colors, all festive parades, he set sail for the port of Lido (it was called going to the sea). The water procession took a short break in front of the island of Sant'Elena to receive the tribute from the monks of that convent, then another pause near the Lido, to welcome the patriarch on board who waited for him on a boat with all ecclesiastical authorities.
Then continued the journey up to the mouth of the port of Lido, in front of the fort of Sant'Andrea, where the patriarch poured blessed water and the Doge, from a small door in the stern of Bucintoro let a gold ring fall into the water , saying these words:
We marry you, O sea, as a sign of eternal dominion!
With this ceremony, the Fiera della Sensa began, with parties, shows, charlatans and storytellers throughout Venice, and in San Marco a market was built with goods of all kinds and from every country, with wooden buildings erected for the occasion. A crowd of visitors, including foreigners, paraded between the stalls and cafes; there was the air of a real international fair.
For the Sensa occasion, the new La Fenice Theater was inaugurated on 16 May 1792. The last "Marriage" of the Republic of Venice occurred in 1796 with the doge Ludovico Manin; with the fall of the Republic he was banned.
The ceremony is repeated today as a traditional festival on Sunday after Ascension Day and, on the clock tower, throughout the Ascension week, figures of the Three Kings are made to appear around the clock itself.