The relationship between electricity and magnetism is called electromagnetism. In 1831, Michael Faraday and Joseph Henry separately illustrated through a series of experiments that an electrical current is produced in a closed circuit due to varying magnetic field. Conversely, a changing magnetic field induces an electrical current.
Prior to Faraday and Henry, the correlation between electricity and magnetism had already been established in the early 19th century. Hans Christian Oersted and Andre-Marie Ampere were some of the major pioneering contributors to the development of the science of electromagnetism. The findings of these previous scientists were compiled and unified into a single electromagnetic theory by James Clerk Maxwell in the 1860s. Maxwell postulated that light is an example of an electromagnetic wave.