Sir Thomas Gresham was an English financier and merchant born in 1519. He is best known for founding the Royal Exchange in London in 1568, which served as a center for trade and commerce. Gresham played a significant role in the development of England's financial system during the reign of Queen Elizabeth I. Gresham is also famous for the economic principle known as Gresham's Law, which states that "bad money drives out good." This principle highlights how people tend to spend less valuable currency while hoarding more valuable coins. His contributions to finance and trade have had a lasting impact on the economy.