Held on the third Saturday and Sunday of July, the Festa del Redentore began as a religious thanksgiving feast marking the end of the terrible plague of 1575-6, that killed 46,000 people - 25-30% of the city's population. Among those who died as the sickness swept through the narrow, huddled streets and waterways, was the great Venetian painter, Titian.
On 4 September 1576, the Senate decided that the Doge - Alvise Mocenigo II - should announce that the people of Venice would vow to erect a church dedicated to the Redentore (Redeemer), in return for help in ending the plague.
Andrea Palladio was commissioned to design a magnificent church on the waterfront of the Canale della Giudecca, one of the Venice islands.
Construction on the Chiesa Santissimo Redentore (Church of the Most Holy Redeemer) was begun in May 1577. After the foundation stone had been laid, a small temporary wooden church was built along with a temporary bridge erected on barges across the Canale, so that the Doge - by this time Sebastian Venier - could make a pilgrimage to the site.
Every year, on the anniversary of the end of the plague, a pontoon bridge is constructed and the same pilgrimage is made...
Palladio's beautiful building - one of the finest examples of what is known as 'Palladian architecture' - was finally consecrated in 1592, twelve years after the death of its architect.
Tonight, as every year, the St Mark's Basin will be teeming with a variety of boats and craft as the people of Venice take to the water to await the traditional grand firework display that, for best part of an hour, will fill the skies with gorgeous eruptions of light and colour reflected in the mirror of the lagoon.
After the last rocket has soared, burst and died, the young people will make their way to the Lido to sit on the beach and await the sunrise over the Adriatic. Then the faithful will follow in the footsteps of Doge Venier and cross the pontoon bridge to make their religious devotions at this historic church.
As whenever we visit Venice, this will be another opportunity to, briefly, inhabit the pages of a this extraordinary living history book.
Visit my flickr albums collection Visions of Venice, for more portraits of this unforgettable city and its people.
Some of those photographs will also be found on the website of of our Venice residence - Hotel Ala.
Other images: Paper sculpture of Palladio's Church of the Holy Redeemer by Ellen Rixford Studio for Gucci's Italian Geniuses series. The ghost of Andrea Palladio draws up the plans for his Venetian masterpiece, paper sculpture about 4 1/2' tall. Panorama by Roger Howard.