Contrary to what it commonly thought Relativity theory was not invented by Einstein but the basic concept was actually developed by Galileo. Einstein realized that not only was motion was relative but time, mass and space were relate as well as well.
In Galilean Relativity space and time were seen as absolutes. This was a result of Galileo not considering the speed of light in his thinking because was unable to measure it. In fact Galileo tried measure the speed of light being the first recorded person to have tried to do so.
From here Einstein developed both his Special and General Relativity. Though Relativity had been used in the development of atheistic theories like the Big Bang, it has also been of great use to Creation Science Cosmology.