What did James Maxwell discover and how?

James Clerk Maxwell discovered the foundations of electromagnetism through his formulation of Maxwell's equations, which describe how electric and magnetic fields interact and propagate. His insights, derived from experimental work and theoretical analysis in the 1860s, unified previously separate concepts of electricity and magnetism into a single framework. He demonstrated that light is an electromagnetic wave, which fundamentally changed our understanding of both physics and technology. Maxwell's work laid the groundwork for modern physics, influencing fields from electrical engineering to quantum mechanics.