Most of the results of relativistic dynamics had already been obtained before Einstein's 1905 paper. Relations between mass and velocity, and mass and energy, had already been obtained from electromagnetic theory. Those developments were due to a widespread belief in the ether as a physical reality, that could produce forces and was endowed with mechanical properties such as mass, energy and momentum. This paper describes the development of those ideas and compares the results obtained by the ether partisans and Einstein's proposals.
relativity theory; Albert Einstein; relativistic dynamics; history of physics
