I’m not asking about the duality particle/wave behavior. I just want to know when did the notion of light being an electromagnetic wave first came up. Was it before or after Maxwell’s calculations of the speed of waves? I am currently reading a book that explain the process by which Maxwell calculated the speed of waves, but the book calls that speed “the speed of light” right away. I remained wondering if by the time Maxwell finished his works on explaining the experiments of Faraday through the power of equations, the physicist community was already aware of light being an electromagnetic wave. If they didn’t know, how much time it has to pass for people to understand that the speed calculated by Maxwell was also the speed of light, since it behaves as an electromagnetic wave. If they did know that light behaved as an electromagnetic wave, how could they even detect this? If the equations that describe the waves behavior where just freshly made by Maxwell?