Wilhelm Conrad Röntgen invented the X-rays. Heinrich Hertz invented electromagnetic theory of light and electromagnetic waves. Johannes Gutenberg invented the Letterpress printing. It was a great invention and was very much appreciated then. Albert Einstein invented the Theory of relativity Rudolf Diesel invented the Combustion engine. Manfred von Ardenne invented the Television. Peter Henlein invented the Pocket watch. Karl Friedrich von Drais invented the Bicycle. Philipp Reis invented the Telephone Karlheinz Brandenburg invented the MP3 technology