Is Light a Particle?

In parallel to studying fermions, people were also studying radiation and light as far back as even way, way before Newton. And so as we're discovering particles, like the electron, and then later the proton people in the background are discussing ideas about quantum mechanics. So this kind of shift in ideas was happening in the 1900s where people were kind of asking themselves, do we even know anything about particles at all? Because our entire worldview is being turned upside down right now.