A certain amount of rediscovery took place. Two walls in the reception room had once featured painted cartouches, but the walls had been covered over and the artwork was not left in place. Working from a photo that just showed the smallest corner of one of the cartouches, McCarty scoured attics and basements for something that looked right. He found them, brought them to the reception room and "they just popped right in."

As the restoration progressed, more documentation was found. One morning, a Ringling staff member discovered a book of photos taken during the Cà d'Zan's construction had gone up for bid on Ebay. Likewise, the photos done by mid-century American architectural photographer Samuel Gottscho provided guidance as the curators sought as much authenticity as possible.

An intriguing decision was made to leave bits of furniture or parts of the painted ceilings as they had been before the work began, a kind of documentation of the process. It makes for fascinating viewing, to say the least.

"The Cà d'Zan is a theater, really," says DeGroft. "It's a stage for the furnishings."

In many ways, the Cà d'Zan is the last of America's Gilded Age mansions, and it is almost an elegy to the era. For one thing, it was completed in December 1925, really at the tail end of all the great architectural exuberance of the era of the industrialists before the era of the income tax. The great houses of Newport came to us largely at the turn of the 20th century, as did the various Vanderbilt mansions elsewhere in the country. James Deering began Vizcaya in 1914. William Randolph Hearst embarked on San Simeon in 1922.

The Vanderbilts and Astors and Belmonts and Deerings (the list could go on to include the Huntingtons and the Stotesburys and numerous others) plundered the palaces and villas of Europe, bringing back objects, furniture and even whole rooms that were crated up and re-assembled. Ringling was a late-comer, and one might even say an arriviste, perhaps more than so many of the other builders of America's great Gilded Age houses-most of whom were born to considerable wealth and simply elaborated on it.

Thus, the Ringlings bought rooms and artifacts and objects from the earlier Gilded Age estates, many of them designed by the architect Richard Morris Hunt for the Astor family; and they also brought in furnishings they admired from commercial establishments, including the grand chandelier that came from the old Waldorf-Astoria on Fifth Avenue, torn down to make way for the Empire State Building.

While others hired the great decorators of the era (from Ogden Codman at the Breakers to Paul Chalfin at Vizcaya) to buy for them and create their decor, John and Mable Ringling, self-taught and self-reliant, did much of it themselves. In the first decades of the century, they traveled widely as John Ringling built his art collection; Mable was taking it all in. And together they honed their tastes in architecture and interior design. Ringling's connoisseurship-of painting, sculpture, and the decorative arts-has been well studied and well documented, but the archival material is sparser when it comes to the house they built together.

We do know that they loved Venice. Various sources tell us that Mable wanted to re-create the Doge's Palace or her favorite hotels, the Gritti Palace and the Danieli. And certainly, though it sprawls like an English country house, the Cà d'Zan stands in full testimony to this love. "It's sort of Palladian in the way it stretches along the waterfront," says Stevenson, "and of course the English country house owed a great debt to Palladio." It's somehow more Venetian than Venice, and at the same time, not Venetian at all; it's a showman's house, and in that, it is also a showy house.

"The Ringlings themselves had a diverse visual tapestry," says DeGroft. "It may have started out as a purely Venetian house, but by the time they were finished, it was something far more complex-Venetian, Gothic, Byzantine and still at the core a 47-room country house. There are two plays here. Ringling was conscious of the American Gilded Age and the new moneyed elite in this country, but he also regarded the rich European heritage that was his as well. This house has both."