From

How Windmills Work

By Cindy Grigg

Very long ago, people used the power of wind to sail boats. About 1,200 years ago, the first windmills we know about were being used in Persia. Windmills may have been used in China even before that. The first windmills were used to grind grain. Later, windmills were used to pump water. They were used to irrigate crops. They were used to drain flooded land.