When
Hermann Minkowski first heard of
Einstein's special theory of
relativity, he realized that it described how
space and
time are folded into each other. He then began a famous paper with the statement:
"Henceforth space by itself, and time by itself, are doomed to fade away into mere shadows, and only a kind of union of the two will preserve an independent realilty."
and then showed physicists how to think about spacetime, rather than space and time.