A steam engine is a heat engine that performs mechanical work using steam as its working fluid.
The use of boiling water to produce mechanical motion goes back over 2000 years, but early devices were not highly practical.
In 1698, Thomas Savery patented a steam pump that used steam in direct contact with the water being pumped.
In 1781, James Watt patented steam engine that produced continuous rotary motion. Watt's ten-horsepower engines enabled a wide range of manufacturing machinery to be powered.
Considering that the great majority of worldwide electric generation is produced by turbine type steam engines, the 'steam age' is continuing with energy levels far beyond those of the turn of the 19th century.