While others had proposed wave-like properties of light before, Huygens was the first to develop a comprehensive theory of light as a wave in the 17th century. His work, *Treatise on Light*, explained phenomena like reflection and refraction using wave principles.
However, it's important to note that:
* Newton believed light was made of particles, which was the dominant theory for a long time.
* Young later proved the wave nature of light with his double-slit experiment.
* Maxwell unified electricity and magnetism, showing that light is an electromagnetic wave.
So, while Huygens was instrumental in promoting the wave theory of light, the understanding of light as a wave has been a collective effort of many scientists over centuries.
