While James Watt cannot take full credit for the steam engine, because of many precursors, he developed the first reliable one. The steam engine, developed over the second half of the 18th century, became the engine for the Industrial Revolution. Steam engines were the power behind locomotives and ships, which provided a faster source of transportation to bring raw materials to factories and to bring finished products to market. Watt is also credited with the term "horsepower" to describe the amount of energy a steam engine could create.