The question of who was the first to invent the telescope (fig.1) is as old as the instrument itself (fig.2). On October 2, 1608, the Dutch Estates General examined an application for a patent for "a device to observe things at a distance" presented by a certain Hans Lipperhey (?-1619) (fig.3), an obscure spectacles-maker from Middelburg, in southwestern Holland (fig.4) . The patent application was rejected on the grounds that, although the usefulness of the device was recognised, especially for military purposes (fig.5), it was deemed impossible to keep the secret of its construction for very long. And especially considering that, in those same days, another instrument-maker - a certain Sacharias Janssen (1588-1630) (fig.6), he too a spectacles-maker in Middelburg, indicated by Pierre Borel (c. 1620-1671) a few decades later (fig.7) as the true inventor of the telescope - declared that he knew how to build the instrument.

News of the invention spread rapidly throughout Europe, and already by April 1609 little telescopes about thirty centimetres long were to be found on sale, (fig.8) at the shops of spectacle-makers, in Paris and presumably in London. In Italy, the new instrument made its appearance at Milan in May of the same year, and two or three months later in Rome, Naples, Padua (fig.9) and Venice (fig.10) , where Fra Paolo Sarpi (1552-1623), a friend of Galileo, had heard news of it already by November 1608.