The Greek philosopher Archimedes is credited with inventing the idea of simple machines. Even though Archimedes improved on already existing ideas from unknown people, it is he who discovered the mechanical advantages of levers that people were already using to pull, push and lift items by hand.
Simple machines include pulleys, wheels and levers. There are two classes of simple machines. Inclined plane, wedges and screws fall in the "forces" class, and wheels, levers and pulleys fall into the "torque" class. Archimedes' work to create simple machines was further improved upon by Heron of Alexandria. In 1600, Galileo Galilei proved that simple machines cannot create energy but simply transform it.