Merchant Royal, also known as Royal Merchant, was a 17th-century English merchant ship that was lost at sea off of Land's End in rough weather on 23 September 1641.On board were at least 100,000 pounds of gold (over US$1.5 billion in today's money), 400 bars of Mexican silver (another 1 million) and nearly 500,000 pieces of eight and other coins, making it one of the most valuable wrecks of all time. The Merchant Royal kept leaking after she and her sister-ship left Cadiz and, when the pumps broke down, she sank off Land's End in rough weather on 23 September 1641. Sept. 30, Lond[on].