Brian Greene in Scientific American:
Einstein shot to fame within the scientific community in 1905, a year christened as his annus mirabilis. While working eight hours days, six days a week at the Swiss patent office in Bern, he wrote four papers in his spare time that changed the course of physics. In March of that year he argued that light, long described as a wave, is actually composed of particles, called photons, an observation that launched quantum mechanics. Two months later, in May, Einstein's calculations provided testable predictions of the atomic hypothesis, later confirmed experimentally, cinching the case that matter is made of atoms. In June he completed the special theory of relativity, revealing that space and time behave in astonishing ways no one had ever anticipated—in short, that distances, speeds and durations are all relative depending on the observer. And to cap it off, in September 1905 Einstein derived a consequence of special relativity, an equation that would become the world's most famous: E = mc2.
Science usually progresses incrementally. Few and far between are contributions that sound the scientific alert that a radical upheaval is at hand. But here one man in one year rang the bell four times, an astonishing outpouring of creative insight. Almost immediately, the scientific establishment could sense that reverberations of Einstein's work were shifting the bedrock understanding of reality. For the wider public, however, Einstein had not yet become Einstein.
That would change on November 6, 1919.