Sailing ships were used for thousands of years, but they were very important from the Age of Discovery to the 19th century. The Chinese admiral Zheng He commanded a fleet of large 'treasure ships' on seven voyages all over Asia up to East-Africa in the early fifteenth century. The most successful and largest fleet in the 17th century was the Dutch fleet (see the Netherlands). For trade and transport the Dutch often used a particular kind of trading ship, called a flute ("fluyt" in Dutch). Transport of people and cargo on sailing ships became rare in the early 20th century.