Newton himself wrote that we usually deal with relative space and time, but we can imagine absolute time and space.
Yes, the principle of relativity was known to Newton, but the other idea, that the speed of light is the same in all reference frames, was new, counterintuitive, and what makes special relativity the way it is.
Yes, the principle of relativity was known to Newton, but the other idea, that the speed of light is the same in all reference frames, was new, counterintuitive, and what makes special relativity the way it is.