Caesar_Rahil said:
According to the Theory of Relativity, "Everything in the universe is related."
Where did you hear this? This is not even close to what relativity says. According relativity space and time are relative. This means that people moving at different speeds have different concepts of space and time, unlike Newtonian physics in which space and time are absolute concepts. This is, of course, just a very brief idea of what the theory of relativity is.
And one more question. If Einstein didn't start it, Who started the Theory of Relativity?
The major players in the discovery of the special theory of relativity were Lorentz, Larmor, Poincare, and Einstein. Lorentz derived the Lorentz transformation equations, which are the most valuable equations in special relativity; I'm not sure what Larmor's contribution was; Poincare came very close to beating Einstein to a full development of special relativity, he is most noted for pursuing the principle of relativity (in the restricted sense) which states that all inertial reference frames are equivalent for the description of the laws of nature; and Einstein took the insights of the special theory of relativity the furthest and did away with the ether.
The major players in the discovery of the general theory of relativity were Einstein and Hilbert. Einstein developed most of the insights for the theory; Hilbert contributed to the math.
edit: Perhaps Minkowski should be mentioned as an important player as well. Minkowski unified the concepts of space and time into a single concept, spacetime. Minkowski played an important role in the transition from special relativity to general relativity. Although special relativity can be formulated without a Minkowskian view of spacetime, general relativity cannot.
So you've got Lorentz, Larmor, Poincare, Minkowski, Hilbert, and Einstein who all contributed important pieces to the development of two theories of relativity (special and then general) in the early 20th century. Einstein's role was the most significant in the development and acceptance of both theories.