Whose theory described electromagnetism?

In the 1860s the Scottish physicist James Clerk Maxwell developed a set of equations that unified electricity and magnetism into one theory of electromagnetism. His equations showed that changing electric and magnetic fields produce one another and can travel through space as waves. Maxwell calculated the speed of these waves and found it matched the speed of light, leading to the profound conclusion that light itself is an electromagnetic wave. His work predicted the existence of other electromagnetic waves, such as radio waves, later confirmed by Heinrich Hertz. Maxwell theory is considered one of the greatest achievements in the history of physics.