Background: Matthew Boulton  (; 3 September 1728 - 17 August 1809) was an English manufacturer and business partner of Scottish engineer James Watt. In the final quarter of the 18th century, the partnership installed hundreds of Boulton & Watt steam engines, which were a great advance on the state of the art, making possible the mechanisation of factories and mills. Boulton applied modern techniques to the minting of coins, striking millions of pieces for Britain and other countries, and supplying the Royal Mint with up-to-date equipment.
Context: The elder Boulton's business prospered after young Matthew's birth, and the family moved to the Snow Hill area of Birmingham, then a well-to-do neighbourhood of new houses. As the local grammar school was in disrepair Boulton was sent to an academy in Deritend, on the other side of Birmingham. At the age of 15 he left school, and by 17 he had invented a technique for inlaying enamels in buckles that proved so popular that the buckles were exported to France, then reimported to Britain and billed as the latest French developments.  On 3 March 1749 Boulton married Mary Robinson, a distant cousin and the daughter of a successful mercer, and wealthy in her own right. They lived briefly with the bride's mother in Lichfield, and then moved to Birmingham, where the elder Matthew Boulton made his son a partner at the age of 21. Though the son signed business letters "from father and self", by the mid-1750s he was effectively running the business. The elder Boulton retired in 1757 and died in 1759.  The Boultons had three daughters in the early 1750s, but all died in infancy. Mary Boulton's health deteriorated, and she died in August 1759. Not long after her death Boulton began to woo her sister Anne. Marriage with a deceased wife's sister was forbidden by ecclesiastical law, though permitted by common law. Nonetheless, they married on 25 June 1760 at St. Mary's Church, Rotherhithe. Eric Delieb, who wrote a book on Boulton's silver, with a biographical sketch, suggests that the marriage celebrant, Rev. James Penfold, an impoverished curate, was probably bribed. Boulton later advised another man who was seeking to wed his late wife's sister: "I advise you to say nothing of your intentions but to go quickly and snugly to Scotland or some obscure corner of London, suppose Wapping, and there take lodgings to make yourself a parishioner. When the month is expired and the Law fulfilled, live and be happy ... I recommend silence, secrecy, and Scotland."  The union was opposed by Anne's brother Luke, who feared Boulton would control (and possibly dissipate) much of the Robinson family fortune. In 1764 Luke Robinson died, and his estate passed to his sister Anne and thus into Matthew Boulton's control.  The Boultons had two children, Matthew Robinson Boulton and Anne Boulton. Matthew Robinson in turn had six children with two wives. His eldest son Matthew Piers Watt Boulton, broadly educated and also a man of science, gained some fame posthumously for his invention of the important aeronautical flight control, the aileron. As his father before him, he also had two wives and six children.
Question: Can you tell me more about the success of the buckles?. Whats the answer?
then reimported to Britain and billed as the latest French developments.