Einstein

Einstein discovered the relativity of simultaneity and, in his special theory of relativity, unified:

space and time;
mass and energy;
electricity and magnetism.

Newton: space, time and particles;
Faraday and Maxwell: space, time, fields and particles;
Einstein, 1905: spacetime, fields and particles;
Einstein, 1915: fields and particles;
Dirac (and see here): fields are particles;
quantum mechanics: spacetime and quantum fields;
quantum gravity: covariant quantum fields.

Einstein's general theory of relativity identifies space-time with the gravitational field.

Carlo Rovelli, Reality Is Not What it Seems (Allen Lane, 2016), pp. 51-107.