In 1974, on the occasion of the centenary of the birth of Guglielmo Marconi, the mint coined a silver coin with a nominal value of 500 lire. This is the first silver coin which, although defined as "legal tender", was not actually intended for circulation, but for the numismatic market (sold at a higher price), since the only intrinsic cost of the alloy had already exceeded the face value of 500 lire. Previously, in fact, only the 500 lire commemorating the centenary of the unification of Italy (1961) and that commemorating the seventh centenary of the birth of Dante (1965) had been minted, as well as the 1000 lire commemorating the centenary of Rome the capital (1970 ), all entered into circulation. In the center, Guglielmo Marconi is portrayed in the center, facing left, "ITALIAN REPUBLIC" while, in the exteriors, the signatures of the modeller Pietro Giampaoli and the engraver Guerrino Mattia Monassi are placed. On the reverse is the image of the Italian peninsula with concentric circles superimposed to represent the radio waves. On the left is the indication of the value, while on the right is the mint sign (R). Along the edge, at the top is written "GUGLIELMO MARCONI" while below are the dates 1874-1974 In the outline: "REPVBBLICA ITALIANA" in relief The diameter is 29 mm, the weight: 11 g and the title is 835/1000 The print run is 689,752 copies.