Merchant Royal also known as Royal Merchant, was a 17th-century English merchant ship lost at sea off Land's End, Cornwall in rough weather on 23 September 1641. On board were at least 100,000 pounds of gold (over 1.5 billion USD 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 times.
The Merchant Royal spent three years trading with Spanish colonies in the West Indies from 1637 to 1640. England was at peace with Spain at this time. The Merchant Royal and her sister-ship, the Dover Merchant, called into Cadiz on their way home to London. By all accounts she was leaking badly after her long voyage.
When a Spanish ship in Cadiz at the same time caught fire just before she was due to carry treasure to convert into pay for Spain's 30,000 soldiers in Flanders, the Merchant Royal's Captain Limbrey saw his chance to make a little more cash for his owners. He volunteered to carry the treasure to Antwerp on his way home.