In December 1999, one of the most complicated watches ever made became the most expensive watch ever sold when it was hammered down for $11 million at Sotheby’s .

The gold pocket watch, which featured 24 complications, was the result of a long-standing competition between two magnates of America’s Gilded Age. New York financierHenry Graves Jr. Henry Graves Jr. and Ohio automobile engineer James Ward PackardJames Ward Packard vied with one another to own a timepiece with the greatest possible number of complications. (Complications are mechanical functions of the watch other than the hours, minutes and seconds.) Packard commissioned 13 complicated watches from Patek Philippe between 1900 and 1927. They included a perpetual calendar with phases and age of the moon, indication of sunrise and sunset, and a celestial chart depicting the constellations of stars in the sky over Packard’s home in Ohio.

Not to be outdone, Henry Graves Jr. also commissioned a series of complicated watches from Patek Philippe, culminating in a timepiece that took three years to design and five years to produce. When completed in 1933, the watch had a different horological function for each hour of the day and included a chart of the nighttime sky over Graves’ home in New York.

Graves died in 1953, and his heirs sold the watch to the Time Museum in Rockford, Ill., in 1968. When the museum closed, the watch was among 80 other pieces from the collection that were deaccessioned and sold at Sotheby’sin 1999. All together, they brought $28 million. The Graves watch had a presale estimate of $3 million to $5 million, and sold for $11,003,500 to an anonymous collector.

Patek Phillippe Caliber 89

In 1989, Patek Philippe created the world’s most complicated timepiece, the Caliber 89, in celebration of the firm’s 150th anniversary. A pocket watch like the Graves and the Packard, the Caliber 89 has 33 functions and 1,728 unique parts. Its complications include the date of Easter, sidereal time and a celestial chart with 2,800 stars.

The most complicated handmade watch ever created has been sold at auction for a record-breaking 20.6 million Swiss francs (£13.4m).

The Graves Supercomplication was delivered in 1933 to millionaire eccentric banker Henry Graves Jr., who commissioned the 18-karat gold timepiece that incorporates 24 complications (functions outside timekeeping), that was hailed as the most complicated watch of its era.

In a Sotheby’s auction yesterday the collectors piece went to an anonymous bidder after a curious set of events saw it wind up on the bidding pillow.

The scion of a wealthy American banking family Graves commissioned the watch as part of a horological duel with his rival James Ward Packard – the luxury car pioneer – to possess the most complicated timepiece ever created.

Graves, who was obsessively competitive as well as secretive, won the competition after eight years of waiting for the Supercomplication.

The star attraction – literally – of the piece is that it’s face displays a celestial chart that perfectly plots the night sky above the financier’s former apartment overlooking Central Park off Fifth Avenue in New York.

The piece is capable of measuring more than just the time, recording sunrise and sunset, contains a perpetual calendar – and chimes the same tune as Big Ben.