This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.
Every schoolbook credits Guglielmo Marconi with inventing radio, and by the ordinary tests, first patent and first public demonstration, that credit is earned. Marconi filed British Patent 12039 on June 2, 1896, the first patent for a workable wireless telegraphy system, and on December 12, 1901 he sent the Morse letter S from Poldhu, Cornwall to St. John's, Newfoundland, the first transatlantic radio transmission, a feat that made him famous and made wireless telegraphy a plausible global technology rather than a laboratory curiosity. He shared the 1909 Nobel Prize in Physics for the achievement, and his company built the wireless networks that made ships safer and news faster for a generation.
But a quieter, parallel claim runs through the same decade. Nikola Tesla filed his own patent, System of Transmission of Electrical Energy, on September 2, 1897, describing a tuned circuit for radio transmission; it was granted March 20, 1900, before Marconi's own United States tuning patent was granted in 1904. When Marconi's company later sued the United States government for wartime patent infringement, the government's defense was that Marconi's key tuning claims were not original at all. The case reached the Supreme Court, and on June 21, 1943, six months after Tesla's death in a New York hotel room, the Court agreed: in Marconi Wireless Telegraph Co. of America v. United States, 320 U.S. 1, it held Marconi's tuning patent invalid, anticipated by earlier work, principally the patents of John Stone Stone and, to a lesser degree, Oliver Lodge and Tesla.
It is worth being precise about what the Court actually decided, because the popular version of this story often overstates it. The ruling did not crown Tesla the true inventor of radio, and it was not really about who deserves the credit at all. It was a patent case, brought by a company seeking compensation from the government, and the Court's holding was that one specific patent's claims over one specific tuning method were anticipated by prior art, chiefly Stone's, with Tesla and Lodge as secondary contributors to that prior art. Marconi's broader achievement, the first workable system and the first transatlantic demonstration, was never in question and was not undone by the ruling.
What the case does show is how thoroughly the closing years of the nineteenth century saw multiple inventors reach for the same idea. Tuned, resonant circuits for selecting a wireless signal from the electromagnetic noise around it were, by the late 1890s, an idea whose time had come, worked out in different laboratories under different names. Marconi built the system that worked, promoted it, and made it a business; Tesla, Stone, and Lodge each described pieces of the same underlying physics, on paper, earlier. Radio's real origin, like the wheel's, resists a single date and a single name, and the atlas records the dispute as itself part of the technology's history, not as a footnote to be smoothed over.