Albert Einstein
According to all of your science books and that one episode of Animaniacs, Albert Einstein, Time Magazine's Man of the Century, invented the theory of relativity. Certainly, when you hear the name Einstein, you undoubtedly will think "He discovered relativity" or "He came up with that E=mc2 equation" or "He was a total sex maniac." Only one of those things is true. (It's the sex maniac part.)
Who Actually Invented It?
Henri Poincaré, mostly. Poincaré was the foremost expert on relativity in the late 19th century and was most likely the first person to formally present the theory of relativity. If you were Einstein and you wanted to write about relativity, you might consider meeting with the foremost expert on relativity, yes? If you answered "yes" to that question, then you're not Einstein at all.
Henri Poincaré, mostly. Poincaré was the foremost expert on relativity in the late 19th century and was most likely the first person to formally present the theory of relativity. If you were Einstein and you wanted to write about relativity, you might consider meeting with the foremost expert on relativity, yes? If you answered "yes" to that question, then you're not Einstein at all.
According to Einstein's famous On the Electrodynamics of Moving Bodies, which contains his theories on relativity, Poincaré, despite publishing 30 books and over 500 papers, is not worth mentioning. It's true, pick up Einstein's paper if you don't believe us, (you won't): Poincaré doesn't receive a single reference, unless you consider plagiarism to be some kind of indirect reference. As a matter of fact, Einstein does not reference, footnote or cite a single goddamn source in his entire paper.
Really? Not one source? Even we cite sources, Albert, and we're friggin' Cracked. What the hell?
Einstein, photographed with God
We don't want to jump to any conclusions here. Maybe Einstein's paper didn't contain any sources because he genuinely didn't read any other current physics texts or papers. Maybe he was seriously that smart. According to Peter Galison's Einstein's Clocks, Poincaré's Maps: Empires of Time, Einstein and a small group of his fellow nerdlings formed a group called The Olympia Academy and would regularly gather to discuss their own works as well as the works of current scientists. The book goes on to specifically mention how Poincaré was one of the scientists that Einstein and his battalion of nerds would discuss.
Shoots that whole "maybe Einstein didn't read any other papers" theory right to shit, doesn't it? It's interesting that Einstein sat studying and discussing the work of Poincaré for years, published a book that featured a theory that was startlingly similar to Poincaré's, and then didn't reference Poincaré once in the entire book. Wait, that isn't interesting? It's plagiarism. It's total bullshit plagiarism. Good luck sexing your way out of this one, Einstein.
Einstein in 1951 (age 72)