A silver watch by 17th century maker David Ramsay led an auction of English timepieces at Sotheby's.
The sale took place in London on December 15, with the piece selling for £989,000 ($1.4m).
It had been valued at £250,000 ($378,825) - resulting in an increase of 295.6%.
The watch is an elaborately constructed piece and displays a portrait of King James I. It's one of many commissions Ramsay undertook for the king.
He was appointed head of the Worshipful Company of Clockmakers in 1632.
A gold two-train pocket watch by Daniel Quare dating to around 1712-1714 made £185,000 ($280,331), beating an estimate of £100,000 ($150,155) by 85%.
The piece was discovered only recently and is the largest of its size from this era to feature quarter-repeating and quarter-striking.
Tim Bourne, Sotheby's head of watches, commented: "Today's offering was unprecedented. It is incredible to think that these immaculately preserved timepieces survived 400 years of tumultuous British history.
"The catalogue read as a 'who's who' of the great British watchmakers through the ages and we are thrilled that collectors and buyers new to the field responded with so much enthusiasm.
"This sale is only the first chapter of a landmark collection which comprises many more treasures and pieces of history."
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