Who put forth the Theory of Relativity in 1905?

Albert Einstein put forth the Theory of Relativity in 1905. More precisely, that year he published special relativity, a theory describing motion, space, and time when gravity is not the central factor.

Einstein’s 1905 paper introduced the principle that the laws of physics are the same for observers moving at constant speeds and that the speed of light in a vacuum is constant. These ideas led to surprising results such as time dilation, length contraction, and the famous mass–energy relationship E = mc².

The broader Theory of Relativity has two parts. Special relativity dates to 1905, while Einstein developed general relativity between 1907 and 1915 and published its complete form in 1916. General relativity explains gravity as the curvature of spacetime caused by mass and energy.

A common mix-up is to treat relativity as a single theory completed in 1905. The quiz answer is still correct because Einstein is the canonical figure associated with both theories, and 1905 specifically marks special relativity.