In January 1929, Hungarian Leo Szilárd became the first person to discuss the resonance condition (what is now called the cyclotron frequency) for a circular accelerating apparatus, in a patent application in Germany. However his main target seems to be the acceleration of electrons, and most of the patent application is focused on describing a device more like a betatron. A couple months later, in the early summer of 1929, Ernest Lawrence came up with the cyclotron idea when he read a paper by Rolf Widerøe describing a drift tube linac. He published a paper in Science in 1930,