Late in the 1920s, a New York watch manufacturer named James Schulz set out to produce a

Patek Phillippe, "Grogan," gold, single-button, split-seconds chronograph with left-handed winder, 1925.

timepiece fit for Jay Gatsby; it was to be the most complicated wristwatch the world had ever seen. Hiring the finest craftsmen in Switzerland, Schulz combined the usual timekeeping mechanism with a stopwatch and chimes, a moonphase dial and a calendar accurate even in leap years, all smartly packed in a tonneau platinum case. He put an unprecedented $10,000 price tag on his invention but for years wouldn’t sell it to anyone. How could he? His timepiece, which was featured in Life magazine and would hold the record as the world’s most complicated wristwatch for six decades, was more famous than he was.

Nor has its fame diminished. At Christie’s Geneva last November, Schulz’s circa-1930 Ultra-Complicated wristwatch sold for $1,090,928, a price comparable with those of the most coveted pieces by the most prestigious maker, Patek Philippe. The same auction, though, also revealed an essential distinction between the two signatures: While the most basic Pateks were selling for $15,000 and more, a second, uncomplicated Schulz, estimated at a modest $1,200 to $2,000, was bought in.

“The Schulz Ultra-Complicated is unique, and also one of the most important watches historically,” explains Christie’s New York expert Adrienne Hines, noting that all kinds of complications—mechanical functions beyond straightforward timekeeping— are increasingly sought after. “But what usually gives a watch collectibility is the maker’s name.” And in vintage watches from the 1920s through the ’70s, two names stand above all others. “There’s no doubt that Patek and Rolex dominate,” says Julien Schaerer, an expert at Antiquorum, an international auction house that specializes in timepieces. “They represent 60 to 70 percent of the vintage market, and the prices are driven higher each year as new collectors enter the market looking for these two makes.”