X-rays were discovered by Wilhelm Conrad Roentgen (1845 - 1923). The discovery was made on November 8, 1895 during Roentgen's experiments on cathode rays. X-rays were so called to emphasize their unknown nature.
The medical significance of Roentgen's discovery was acknowledged with the awarding of the Nobel Prize in Physics in 1901.
Some earlier inventors paved the way for Roentgen's 1895 breakthrough, including Johan Hittorf, who invented the Crookes tube, and Ivan Pulyi, who developed the vacuum discharge tube.
Nikola Tesla also experimented with X-rays using a single-electrode tube, also known as the Bremsstrahlung process.
Thomas Edison followed Roentgen's discovery by developing a fluoroscope suitable for medical applications.