to his English ancestry, he developed a long-lasting connection with the English royal house, but was equally sought-after by other monarchs as an appraiser, intermediary in gem trades, and buyer of jewels that they wanted to pawn or sell. Cletcher kept extensive notes on his trades and produced drawings of the most notable objects, the majority of which survived and are held today by the Museum Boijmans Van Beuningen in Rotterdam. In 1625, Cletcher was the agent of choice when Charles I of England sent his wife Henrietta Maria to the continent to pawn away what she could of the English crown jewels in order to alleviate Charles' financial troubles. Henrietta Maria traded one of England's most impressive pieces of jewellery–the hat jewel known as the Mirror of Great Britain–to Cletcher, who recorded the item in his sketchbook with the note that it had been "commissioned by Coninc Jacobus" (Charles' predecessor James VI and I). The Mirror consisted of three large diamonds, one from the Great H of Scotland, with an equally large ruby, and hanging underneath, one of the largest cut diamonds that existed in Europe at the time, the 55-carat Sancy. While Charles was able to redeem the Sancy some 13 years later in 1639, the Mirror was broken up by Cletcher and never returned to England. Over the next decades, Cletcher became a major force in the Northern European market for diamonds and jewellery. It has been speculated that Cletcher was the buyer or middleman when Henrietta Maria attempted to pawn the Three Brothers in 1643/44 in an attempt to finance Charles' army in the First English Civil War. The Brothers were a crown jewel that was already 250 years old by then, and which had been owned by Duke John the Fearless, banker Jakob Fugger and Queen Elizabeth I. The jewel is considered lost since 1645, and might have been sold or broken up by Cletcher after acquiring it. In 1644, he engineered the purchase of the 35-carat Beau Sancy diamond–the smaller sibling to the Sancy–from the estate of the late Marie de' Medici by Frederick Henry, whose appetite for luxury had grown with the successes of the Dutch Republic. Cletcher brought the Prince in contact with an Italian gem dealer living in Amsterdam, who received 80,000 guilders for the Beau Sancy. Cletcher recorded the transaction with great satisfaction in his notebook, as he believed the