Audemars Piguet has acquired the S. Smith & Son Astronomical Watch, known as the "Grosse Pièce," a timepiece of great importance in the brand's history, at a Sotheby's auction on December 8, 2025. Completed in 1921, the Grosse Pièce is a pocket watch with a 19-function complication, distinguishing itself as the most comprehensive astronomical watch and one of Audemars Piguet's earliest creations to feature a star chart. This historic piece, which has been hidden from the public for over 100 years, will return to Le Brassus, Switzerland, on the brand's 150th anniversary, symbolizing the company's commitment to preserving its watchmaking heritage and the art of Haute Horlogerie.
Audemars Piguet wins its signature "Grosse Pièce" timepiece at auction
Audemars Piguet has won at auction one of the most important timepieces in the company's history: the S. Smith & Son Astronomical Watch, commonly known as the "Grosse Piece." Completed and delivered to a customer in 1921, the piece was hidden away in secret until the 1990s, and its return to Audemars Piguet in 2025, the 150th anniversary of the company's founding, symbolizes the company's commitment to preserving its watchmaking heritage and the art of Haute Horlogerie.
The Grosse Pieces is an astronomical pocket watch commissioned by S. Smith & Son, a watch shop in London, England. The project began in 1914 and was completed seven years later in 1921. The dial displays hours, minutes, and seconds, a perpetual calendar, a chronograph function, a moon phase display, sidereal time (the time it takes for the stars to return to their original positions as seen from Earth), and the equation of time (the difference between the time when the sun is at its highest point in the sky and 12 o'clock (noon)). It also features a minute repeater, a grand sonnerie, a petite sonnerie, and the only tourbillon in an Audemars Piguet pocket watch at the time.
Its greatest feature is the star chart, which depicts 315 stars based on the London skyline. By combining sidereal time and the equation of time, this is the most comprehensive astronomical watch available to assist professional astronomical observations, and it is one of Audemars Piguet's earliest watches to feature a star chart.
With 19 different functions, the Grosse Pieces is the most complicated pocket watch in Audemars Piguet's history, alongside the legendary Universelle from 1899. Like the Universelle, it is a living testament to the établissage (division of labor) system of the Vallée de Joux in Switzerland, and an important icon of the history of the specialized artisans who brought together the most complicated timepieces of the early 20th century.
After this precious timepiece was delivered to S. Smith & Son in 1921, the Grosse Piece disappeared from public view for a long time, known only from design documents, archives, and limited photographs. The pocket watch was then housed in the renowned Olmsted Complications Collection, where it remained under strict security and was treated as a "treasured treasure" only available to a select few.
The situation changed dramatically on December 8th, when the Grosse Pièce was put up for auction as part of the Olmsted Complications Collection at Sotheby's Important Watches Auction in New York.
Audemars Piguet has therefore acquired it, in keeping with its mission to preserve watchmaking heritage and the art of Haute Horlogerie, and is returning it to its home town of Le Brassus.
Audemars Piguet has announced plans not only to preserve this historic timepiece as a collectible, but also to share it with enthusiasts around the world. The Grosse Piece will tour the world over the next few years, appearing at Audemars Piguet houses and events.
It will then be exhibited at the company's museum, the Musée Atelier Audemars Piguet in Le Brassus, where it will remain open to the public as a key piece in the brand's history of complication movements.
