The most important part of Einstein's theories is that they combine space and time into one common entity, space-time. This idea didn't come from Einstein but from Minkowski, but Einstein was the one to understand what itmeans. Which is why today you cany buy a bobble-head Einstein but not a bobble-head Minkowski. Sorry Minkowski.No, the idea came from Poincare's 1905 paper, and further developed by Minkowski in 1907. Einstein missed it in his papers, and even admitted:
Since the mathematicians have invaded the theory of relativity, I do not understand it myself anymore.Almost everything she says was from Poincare and Minkowski, and not even understood by Einstein until around 1915. She adopts a modern geometrical interpretation that Einstein rejected most of his life.