Lorentz lived from 1853 to 1928 and became known as the "Grand Old Man of Dutch Physics". He came up with the idea that the laws of nature must be invariant to a change of coordinate systems. The consequences of this were that time and space variables needed to enter into equations on an equal footing (same order of differentiation, etc.). Maxwell's Equations were readily made to be "Lorentz-invariant" and were then seen to be somehow very fundamental. These ideas laid the basis for the theory of special relativity a few years later. But new theories were always tested against this condition - if it wasn't Lorentz-invariant, something must be badly wrong. Schrödinger ran into this problem when he first tackled quantum mechanics.