Special relativity came first, and it was actually to solve paradoxes relating to fast-moving magnets. Maxwell’s equations always produced a fixed speed of light, which breaks Galilean relativity, and has Lorentz symmetry baked in. Just gluing that on to Newtonian mechanics causes problems.
His solution was to work out a weird, different but observationally equivalent mechanics that would work. Decades later, it was realised matter is waves which internally move at the speed of light as well, so it’s not that weird after all.
Special relativity came first, and it was actually to solve paradoxes relating to fast-moving magnets. Maxwell’s equations always produced a fixed speed of light, which breaks Galilean relativity, and has Lorentz symmetry baked in. Just gluing that on to Newtonian mechanics causes problems.
His solution was to work out a weird, different but observationally equivalent mechanics that would work. Decades later, it was realised matter is waves which internally move at the speed of light as well, so it’s not that weird after all.